Gmas picked up this topic and added
As far as the 60 A alt... first why would you need 60 a from each... in todays useage... but, I suggest that you look in the Ford manual for it... it can be had... and it has been put on a lot of civilian / military.. gear driven engines... and they came from the factory that way... check the TC's and you will find what came/w/what. the reason's you don't want the 60 amp alt is because of the acelerated wear that the driven gear get... not to mention the rubber copler which sheers when you load the altnator up... so the sales man is doing you a favor and not selling you something that will cause you to regret it... but, again I found that the original 337/02's came with 35a altenators made by Motorola.. Ford and Prestolite didn't start making the 60a 24v gear drive until 1967... Hmmmm like in after 66... before that their were Delco GENARATORS... As to the belt driven altenators... they were an option again for the working plane... they were driven off the accessory drive which also drove the gear pump and later on the vacuum pump only... Some of the Aerial Photo planes and ones used by police forces in the south... used this accessory drive to power a large altenator... 120vac.. to power onboard accessories... or for a spotlight... Again the combination did not work out... as the accessory drive had problems with the bevel gears in it getting oil... condensation built up in the area and caused the shaft to rust... stoping the gear from free floating ... causing it to be eatn up putting metal in the mill... and may have been responsible for a lot of the 360's engine problems... I believe they are still used though for the 337's that are air conditioned... they drive the compressor from that shaft. military... use only...nope.. it can be found in the Cont I0-TISO PARTS book... even today...
Dave Zavoina replied
As far as the alternators go, do a load analysis using the vacuum tube type radios that the O-2's had to use to accomplish the mission.
Gmas then said
Your Vacuum tube radio... that the military never used much The only ones that were tube was the MK 3's and 12's... and they did not used them long... they went to the wolfburgs..or Collens yes I do have the manual... see... so I can walk the walk.. and definately punt... If you go back to your MK's you will find that at 24 volt you only are drawing half the current... that you would if they were on 12 volt. Therefore if you had a 65 amp 12volt... altenator.. you could get buy easily with the 32 amp 28volt motorola altenator... which became the 38 amp... See the military likes 100% overload factor...
So They gave you two of them... and without the gear pump... being electric... it furnished more than enough power... It was later on that they started adding more power useage and started to decrease their overload factor to 50%... when they did use the 65 amp 24 volt altenator... which I think were really 60 amp... giving you over 1500 watts of power from each... I don't know of anything on a airplane... which is needed for flight that would use over 3000 watts of power... unless you want to use it for a heater... or lighting up the sky.. but, if it makes you feel better... I will say that you would need 8 to 10,000 watts for some applications... though I haven't seen it except on commercial JETS... and if you drove those type of alternators.. you wouldn't have much power left to fly the plane... kina like yours... where you have the old junk... (tube type total calc by my sheet 28amp..)... I would either go to the wolfburgs... or else get something solid state... i.e the king KX 155 only uses 6 amps in transmit and .5 amp... when listening... now if we have two of those radios like in my plane... I use a whopping 1 amp on recieve and If I could transmitt on both I would only use 12 amps of my 38 amp altenator... Ok.. xponder... 1 amp DME... 1.5 amp... ADF... 1 amp... Audio panel.. 1 amp... with marker becon.. reciever... and the new device called the GPS... 2 amps... Wow.. anin't technology great... Yep I need to go get the 65 amp.. altenator... I need more power... of course what I will do with it... I don't know... guess I could run a air conditioner... but, then again at 10,000 feet.. it already kinda cool... But, for your information... I shut one altenator off... because I don't need it... and the system that Cessna had of balancing them... doesn't have to work... If it ever quits.. hey I got a spair.. so you see you don't need a 65 amp altenator... two 38 amp.. (added togeather are 76 amps) are enough to power anything in todays airplane... course I am sure their are some submarines that run completely on electric that you will find and will say I'm wrong again...
Dave Zavoina replied further
The airplane was designed in the early sixties to use radios designed in the early fifties. The inverter used to power up the two flight gyros as well as the ac in the other avionics required no less than 25 amps of power at 28 volts by itself. I'd sure hate to shoot an approach on one engine with most of my avionics out due to having to shuck electrical load because I didn't have enough electrical power to pull the load. The TACAN, ILS, ADF all used AC power in their power supplies. This was government mandated and not Cessna design engineers ideas. All military aircraft could use any of the equipment installed in any other. This kept depot inventory at a reasonable level.
Gmas then asked
Besides the two 35 amp altenators on your bird do you have the two gear pumps... off the accessory drive.. it seems that early military types didn't have both... they only drove off the frount engine... strange that they would only hve one pump... when we know they liked redundcy.. I think it was only one or two years before they put the pump on both engines...
Dave Zavoina replied My front alternator is gear driven and the rear one is belt driven off of the prop flange where the spinner bulkhead would bolt on a civillian aircraft, howrver the early O-2's (built with 67- serial numbers) had two gear driven units. All of the O-2's were delivered with only one hydraulic pump on the front engine, and no vacuum pumps. This makes maitenance on the accessory housings much easier some times. My plane also has a NI-CAD battery mounted just inside the baggage door. That also makes front engine work a little easier too, without working around that plastic box on the front firewall. I also have fire detectors on the rear engine, I hope that they don't have to work, but they test O K on each run-up Fair skies and tail winds....Dave
more from Gmas
It seems that the reason they drove the rear alt with a belt... according to one of the guys that worked on them... is that they used a 400 cyc altenator.. that put out A/C on some of the commucation relay planes. wow what a booring job.. flying around in circles so that the ground troups could link up with HQ etc... although he said also that they had other applications and that some of the backs of the mixmasters were filled with all kinds of electronic gagetry... that this altenator drove. He said that the EW officer kept them away from the insides and kept the equipment covered up... but, as he says.. they were up to no good.. one had a 5000 watt transmitter on it one time .. and a trailing antenna device placed under one of the rudder strikes.. another had a TV camera mounted in the place where the aeral camera went.. he says that it looked like they were making a movie... with it... but, that it had a couple of transmitters in it to send the picture back... He also said that they had one set up to guide in un-maned drones.. and that the guy in the back.. had a second set of aircraft controls.. seperate from the mixmasters... but, was complete down to the rudder pedals.. and it too had all kinds of antennas hanging all over it.... He used to work on the O-2's in VN and although not in the CIA.. he said that they were their too.. He said that the Air Force flew most of these birds at night... and come back early in the morning.. with some of them having holes that needed patching... from small arms fire... so they must have been doing something out their all night... probably sam sites... He chuckles at the though ... so he said.. about how loaded up they were.. with all this electronic junk.. and rocket.. and guns.. and how the book said that they were not supposed to go over a certin weight limit... and how the maintance chief... tore the weight limit page out of the book one day and threw it away... when he was arguing with a EW officer... he said that when the chief got back.. he told 'em to put what ever they wanted on it... and didn't care if it ever got off the ground... he went on to say that when they left.. everyone was betting if it would get off the ground... because it was so overloaded... but, he said it did... kinda in ground effect for a while... down the runway... and then lifted off.. and flew away... and right after that the hurckey birds left with the drones under each wing.. He has some interesting tales about the birds... and how rugged they were... but, as he said he wouldn't fly in them or any small plane to save his life... fly safe.. GM>
Dave Zavoina replied
I've got a 68 O-2A, and there isn't a guide per se, the military used a work card system similar to the CAMP system used on corporate jets. I have a copy of the USAF -6 (Special Inspection Requirements) but it doesn't help much. I've been using FAR 43, Appendix D and the guide from the CE-337 Service Manual since I got mine in 1989. The Service Manual is for the 1965-1969 year models
GM 337 Clubadded
I don't think you will find a manual as such... I had one of the guys who used to work on the O2's in the military and he said they did not use a "TO" on that bird... instead they had a checklist similar to AC-43 apx D.. and a modified Service manual ... which is just like the one that was produced for the civilian versions. It had a military cover on it and showed just the military version... with another manual which was the Shop parts manual. They got both of these manuals when they went to the mechanics school. Supposedly they had a Cessna field rep teaching them... and they worked on the birds while their.
to answer your question about your annual... the 337 in the military was not on an annual it was progressive inspection. You can elect to have it either way and we suggest that you do a annual... else you are forever working on the bird. To be legal... you can use either 43=13 apx d or you can use the manufactures checklist provided in the frount of the Service manual for your year bird. If you use the 43-13 you must write it in the log book... otherwise you can spec manufactur specifications. The inspection parts are the same... except for the addition of the military items... like radio rack in the back extra windows... etc... these items are not covered in the specific item portion of the civilian check list but, could be considered listed under the overall inspection section. The FAA will buy the civilian manufactures checklist because the airplane was taken from the civilian assemble line... so the approprate s/n and year will work... ie. it make no differance that you have the 15x5.5 wheels and brakes* that the military used... they are covered in the manual under wheels brakes and tires... check for wear.. and are listed in the part manufacture... Cleavland or McCully in this case... for wear limits...
If I were you I would grab the Cessna Shop manual and Parts manual ... hot foot it down to the FAA field office and show them what you intend to do.. for your annual requirement.. I think you will find that they are in agreement... and you can use the manufactures manuals... Its them things like gun sights and rocket launcher switches... that their gona want to see disabled... and noted so they cant be used... on the 337 form... they get real nurvious otherwise... and take it personally.. (smile)
*Debate on aspects of this mail went on for some time see under the headings Brakes and on other pages in the archive lists
Dave Zavoina replied
Just about any reputable avionics shop can install an autopilot, but in my experience (twenty plus years os maintence), the best thing you can do, if possible, is to fly the plane to Mineral Wells, TX, where the two primary autopilot manufacturers are, and let them install it. You will have less (i.e. cheaper) problems with the autopilot in the long run. The manufacturers are S-TEC Systems and Century Flight. I've had dealings with both, and it wasn't an unpleasent experience.
GM @337 Club... replied
Try the Gyro house in Alburn, Ca. The have an expert that works their... who can fix it... Hope this helps... G.M>
Bob Attwater added
I hope you get someone to repair the old C300 autopilot. Don't let anyone tell you they are not worth repairing. When i bought my 337 (1970 E model) 20 years ago its autopilot was not functioning, and i was told even then they they were no good. I replaced all the capacitors with modern ones, (an essential first step), and set about tuning it up myself - now on a 3 hour trip from Melbourne to Sydney (i am in Australia) the altimiter does not move any more than the thickness of the line at hold altitude, and my GPS, which i coupled, does not move off the centre. They are a good serviceable unit once you get rid of those old capacitors. All i need now is some wings ! (see my wing spar inspection request) Regards
Tony Portella also added
Check with Mr. Paul 1-800-561-6448 or 904-437-5792 Richard or Kevin Rosa, tell them I send you, Good luck
GM 337 Skymasters Club replied
Yes you can make your own... if you can't seem to find one... but, the people who make the autopilots.. like king and S-tec should be able to furnish you one... if they cant.. then you need to go find one in your year/model plane and ask to open the cover and copy its demensions...and take it to your local mechanic and have him make one out of the same type of material.. same no of rivets... etc.. then BEFORE putting it on.. go to the local FAA office and show them what you are about to do.. they wil assign you a field inspector...who will be the one that will sign off the Form 337 when you are done... the mechanic can install it.. the IA can sign off on the form and return it to service and the FAA will sign off as a legal itme.. approved... we have done it before.. and why cessna did not put the bracket in every airplane.. is beyond us... but,it goes in fairly easy and then your autopilot items... new cables etc.. go in.. most of which cessna still will provide.. as after manufacture parts... which are approved parts...(politically correct) Hope this helps.. G.M> 337 Skymaster Club
Later GM 337 added
Try these guys and see if they can come up with the part.. http://www.hillaircraft.com/
Darrell McCalla then posted another message at a later date
To refresh: M337 68-11122 wanting to install an S-TEC 50 autopilot but of course there are no bracket for the bridle cable from the servo to the bellcrank installed since the military did not want an autopilot. None to be had anywhere!
Ok! I've gotten the brackets built for the bridle cable to pass through and the plate that holds the bracket to the wing via the trailing edge of the leading edge skin rivits(at the J stringers) ( I hate to think I've got to drill out 3 rivits on top and 3 on the bottom of the wing.) Thank goodness that Cessna put the hole for the cable through the plate behind the bellcrank. The vertical position is not a problem but the horizontal postion is. How far from (station 177) the rib outboard is the edge of the bracket plate mounted? The install drawings from S-TEC while good only show the bracket as "existing". So far in looking around in every book i can find no info. Also, all of the 337's around have autopilots in them and I would have to remove the servo to get at the bracket.......that is a last resort. Any help?
GMAS 337Skymasters Club replied
Darrell... I checked the avonics manual.. for the autopilot installation and its associated hardware.. and your right... the O2A in 68 did not have a auto pilot... and you will have to default to the civilian version to get the pattern and location of the servo .... I would suggest that you get in touch with Cessna factory and ask them to send you a copy of the blue print showing the hole pattern and location... they will probably fax it to you.. or give you the dimensions over the phone... I would try someone like Cliff Ives over their.. or someone in engineering... and explane the reasion being your installation is going into a O2A. Another source I would try would be King Avonics factory rep.. they have speicalist that are in different areas and may have come across this before... I cant believe that S tec does not have the drawings from cessna for the 68 civilian model... which would be similar... that shows the hole pattern for your bracket... and would have the location from the rib and spar. If all else fails .. you have to resort to the old ... go look see and measure from a existing one... I would not think you would have to remove the existing servo to get to where the bracket mounts... you should be able to get several of the rivits location on the wing... from just looking... and then check the spacing for the others... go from rivet center to rivet center... they have a little dimple in them... I usually use a compass with sharp points to do the locations... and then transfer them to the one I am working on... Most of the time the guys in the avoinics shop are the ones that put in the autopilots... as it requires a repair station FCC license to put one in and check it out... though I would think a A&P could.. the FAA usually likes the guys over in the radio shop to do it... as it has them wire looking things... coming out of the back... and they are more equiped to handle this kind of stuff... but, we will put the inquiree in on monday.. to see if we can get any help for you... G.M>
Darrell McCalla then said
The shop is going to install the autopilot and the servos. The pully bracket is what is in question. I'll try to come up with a 68 civie drawing to try to located the bracket. It can only go 1 or 2 inches either way because of the location of the rivits. The drawing sent to me from s-tec is a scale drawing in the vertical not horizontal so thats why I can locate the bracket form it. BTW an IA is installing the bracket for me at my home AP. Then I will take the AC to the S-TEC dealer
GMAS 337Skymasters Club replied
I am still at a loss... I guess I am still not following you as to where the bracket is supposed to go... the way the autopilot part in the wing.. has no pullys... it goes from the bell crank arm... located in frount of the main spar... by cable through it... to the chain that goes around the servo... located back in the middle of the outboard bay... the servo.. has its action applied to the bell crank arm.. which then transfers it to the push pull tube... and on to the aleron... are we talking about the bracket that mounts the servo... ie where the chain goes around... ya got me kinda confused as to what were looking at here... but, ya seem to have it under control.. as I read above... G.M>
Darrell McCalla replied
The question is again where the pully bracket (that holds two pullys)for the servo bridle cable to roll over so there is no slop... This is on the cessna drawing I got from S-TEC install drawing that they sent me.... And on the additional items list that comes with the autopilot... Could it be that the Cessna autopilots just used cables through the hole in the spar and no device to support the cables.... This bracket was built from a Cessna factory drawing but was dated mid-70s. The Cessna parts places have the part listed but not available so I had it built...... Maybe? I'm guessing about the Cessna autopilots not having a dual pully bracket..
GMAS 337 Skymasters Club replied further yes indeed you have the two pullies that guide the cable around the corner... We found the AF 394A... but it appears that their are three parts to the bracket. the forward part with the pullies on it is paraell to the main spar... a stiffner plate is perpendicular to the servo mount plate which is again parell to the main spar. The drawing I have does not show any demensions on it however... Another part that shows a different no is the bell crank...it has another section added to it for the cable hook ups for the autopilot. It refers to the autopilot installation and maintance manual... which says that cessna did in fact have a addition kit to install the autopilot. In checking with our sources we found that S-Tec has the manual... and the drawings for the installation of your plate. It is located in the Cessna autopilot manual. My microfish does not go into the installation of the plate... it assumes that you have a civilian model.. that already has the autopilot installed... The best that I can determine is that it is located at the 40 percent cord tie... their are 4 rivit -4 on the top forward plate containing the pullies... and 4 on the bottom... then the stiffner has 4 only on the bottom and the mounting plate... has 2 on the top and 2 on the bottom... The actuator is mounted with 4 bolts... now I am only going by the drawings... that I have... I do not have a 70's series in right now.. so I cant give you any deminsions as to where it is located. the only referance that the manual gives is that it is forward of the access door.. which is the large one in the right wing tip... sorry I guess I can not be of much help...without having the plane or one like it here. We suggest that you contact Cessna for the installition of the bracket... and have them send you the drawing and locations for the plates as your going to need them to show on your form 337... for the FAA
gmas replied
first off... I don't think you will get the FAA to field approve the modification... as the hull is a pressure vessel... in not so may words... and by putting the baggage door in you disrupt the contentuity of the vessel... Second... you have this big valve in the way... for the rear engine fuel slector... right where the door should go... if my memory serves me right.... Third... how do you propose to seal the door and keep it from getting unpressurized inside... Nope not a good idea.... Tell him to get a t-337.... 1978.... it already has the door in it... if he doesn't know where to get one call Aero Financil in Livermore, Ca.... they have a T-337 with a bagage door in it... from what he gets selling the P-337 he can buy this one and save the differance on the door... Again it is almost impossiable to get the door on the P series.....g.M> 337 club
GMAS 337Skymasters Club replied
Yep they are the only thing that we use on our engines ... turbo or normal however you have to make sure that the cyc ex casting area has enough material left... to make the gaskets seal correctly.. and transfer the heat. another important factor is to make sure you properly torque them as they are a "crush" type of gasket... once used.. they are history... and can not be used again. We also use a little engine oil on the face of them to help them seat in... Once installed correctly they seem to almost last the life of the engine... and prevent burning of the ex pipe flange and cyc area. If cont engine wanted to do anything to help out their engines they could have made the exhaust port a 3 or 4 bolt one... instead of two... to help distrubute the stress... but, we have to work with what we have.. and the "No-Blows are the best we can get right now... Hope this helps... G.M> 337Skymasters Club.
GM 337 Club... replied
Gee... I thought I said that the service manual showed that there were two types of brakes but, according to you findings I guess I will have to tell the guy who has the O-2 that he should take off his 15.5.5 wheels and tires because they are not supposed to be on the plane
Dave Zavoina added
the tires are not 15 x 5.5, they are 18 x5.5, you will not find a 15x5.5 tire in any aircraft catalogue.
GM 337 Club... replied further
Yep your right... I misstyped the 18 for the 15.. sorry... I was going by memory... but, I did... and still stick to my guns about the brakes... in the service manual (Civilian) you will see that the mains can have two different types of wheels... 6 and 18 inch... which cover the military and civilian ones... that used both of them... Ahaa... you would like to see a F337... it is cromated inside and out... seems the Reims plant did it the old way... but, you cant fault Cessna for not doing it... according to the military it was a spec.. but, civilian you could for a few dollars more have yours done when you ordered it... back then from the factory.. but, again the logic that Cessna used was that the airfraim would be shot in 5 years and when they used alclad... it would last that long... heck.. when taken care of and hangared we are now going on what... 20 years... their attitude was to keep the weight and cost down... so they had logic for what they did back then... when we do a repair we alumaprep, alodine and cromate the parts before assembly also... it is more a personal standard of work... than extending the life of the plane.
Dave Zavoina then said
About the brakes, forget the civillian service manual, he's not working on an airplane covered by that manual, so the two different types of brakes in that book don't mean doo doo. If he changes to those brakes, then he must comply with an STC, or apply for a field alteration.
gmas replied
The best way to get one cheep is to go to the army navy store and get some 1/2 inch wide webbing and then go to an apolstery shop and have them sew it into a cargo net for you....
Dave Zavoina
The data plate should be located on the foreward cabin door frame. It will not contain the USAF tail number, but will have the Cessna Construction Number stamped on it, ie, M337-XXXX
I then asked
Isn't this the same position for civil models as well??
Frank Benvin replies
It's on the underside of the tail feathers
GMAs337Skymasters Club replied
Yes and no.... you can put a camera hold in the area behind the pilots seat... it was the original area for the view finder... and you can find the parts and pieces in the shop/parts manual... as to the larger 16 inch hole.. nope.. It would take all kinds of re-riging the controls as well as removing a bulkhead and then adding stiffners ... a piece of 063 doubbler under the center section... if you again look at the parts manual.. and study the illistration carefully.. you can see all the additional stuff that is required to go into one that has the factory camera port... I have a skymaster that has one... and when I went to change the ADF ant as well as some of the other things.. I had to relocate stuff... to make it fit.. I have only used my camera port 2 times... once for doing some aerial photog during a flood and the second time we put a video camera under the plane.. but, now that cameras are smaller and lighter.. the day of the camera port is pretty much gone... film is out and video is in... though we still have the K17 cameras.. we don't use them much any more... hope this helps.. G.M>
Dave Zavoina
The nose gear Schrader Valve is located on the aft upper portion of the strut. To gain access, you have to remove the inspection panel just aft of the center nose gear door(the one that stays open when the gear is down). You may have to undo the two bolts that hold that door open to gain acess to three screws on the leading edge of that panel. Then you'll need a really skinny arm to get the hose to the valve. Good luck.
Bob McGrath added
So far so good. BUT the weight of the airplane must be off the nose gear when air is added to the strut. This means that your skinny arm is extended almost to the elbow through the inspection hole. IF the nose of the airplane comes down while your arm is in there, you have a badly mangled arm! Make sure you have help to ensure that such an accident doesn't happen.
GMAS 337 Skymaster Club also added
Wow... you really need to go get your service manual back from your friend After reading all the good advice from the other contrubitors... I would only add that you put a jack under the nose post located behind the acess pannel that you have to take off... after that you need to release the nose gear by overriding the down lock mech.. and manually pushing the wheel up.. part way... to where you can see the valve... remove the yellow cap... you do have a yellow cap on the valve don't you... and inflate with nitrogen.. to the specific pressure... like around 35 lbs.. and where you get the proper distance from the bottom casting to the top... of the strut.. with the weight on it... somewhre around 2 to 2.5 inches.. if the strut is flat.. you might want to overhaul it... because it will go flat again... replace the cap ... replace the screws... pull the wheel down and make sure that the down lock engauged... then remove the jack.. but, you really should have the service manual their to follow the proceedures... the FAA requires it... along with a mechanics license... because it is not a simple proceedure.. Good luck... G.M> 337 Skymasters Club
The fuel flow meters on my 1967 T337B read considerably different from one another. I.e., the rear engine reads about 16 GPH for a 125 degree rich of lean setting at 75% power, while the left reads around 14 GPH.
Also, just when leaving the mixture knobs at full rich settings, I notice that there is a lot more fule being pumped into the rear engine than the front.
How do these gauges work? Can they be a lot off sometimes, or do they wear and lose accuracy, etc.?
GMAS 337Skymasters Club replied
yes they do wear out and need to be calibrated or tested every so often... Cessna did not expect them to be in service as long as they have when they built the plane... but, two gallon an hour different is way off... and my first question is ... did they ever read the same... and my second is when did they start moving away from each other... Somewhere in the past messages I went into detail on the operation of the gauge and how it works, what effects it and what can go wrong... The service manual also has an explanation of the fuel system and how it works... However, my discussion was a while ago and I will be more than happy to go through the system and its operation again.. but because of space will keep it to a min... I suggest that you try surching the database for the old article on fuel system.. that I wrote before for further referance... and reading. Ok.. now the way it works... The gauge is really not a fuel flow gauge but rather a pressure indicator i.e.. when you are idleing you are using about 3-5 lbs of fuel pressure.. which equates out to about a gallon... a low fuel flow... when you are running wide open... or full power...you are producing about 18 lbs.. of fuel pressure... which works out to 108 lbs of fuel or about 17 gallons per hour... now the injectors and the lines are of a preset size... and to increase the fuel flow to the engine... all we have to to is increase the pressure... which then works out mathmatically as a proportional system... more pressure more fuel flow.. but, now lets get to the problems part... lets block off all the injectors.. and in theroi pressurize the system... what happens to the pressure gage... it goes high ... and thus indicates high fuel flow... but, we know we have blocked off the injectors so that no fuel flows... and the engine won't run... it lies.. on the other hand.. lets take the injectors off ... and let the fuel flow freely.... the pressure guage reads low and says that we have no fuel flow... but wait what is that all over the floor... yep.. all the fuel... again the guage lies... now logically thinking and keeping the two end points in mind... we can deduce that if we suddenly start getting higher fuel flow readings...for the same engine rpm/mp.. fuel pressure goes up...indicating high fuel flow... maybe we have a blockage somewhere... The first place to start is the injectors.. the end user... you did clean them at your last annual didn't you... like the service manual says too... and if you are going to clean them... get a mechanic to show you how... and FOLLOW THE MANUAL... on the proper way to do it... no manual.. no cleaning.. as you can mess them up if you don't follow the manufactures instructions... No you don't need the Jazzzie injectors... the original ones work just fine... but, you can mess them up... and if you do.. they cost around 90 to 100 bucks a piece.. set of 6 required per engine... On a note here we have found that most shade tree mechanics/pilots haven't got a clue that Cessna produced probably one of the finest service manuals for the skymaster... and keep coming back for ... how too.. questions.. which we keep refering them to the service manual... for... and suggest that they check the book before they take the next step.. which most mechanics have started charging office time for....(costing money...) If you don't have the one for your series skymaster... we suggest you try and obtain one... as they are a wealth of information and required by the FAA if you or your mechanic is going to work on the plane.... we have heard from several members.. that got cited by the FAA while working on their plane doing routine maintance and not having one handy... one mechanic lost his ticket for 90 days for the same... The FAA kinda takes the manual seriously... and it is required by regulation... ANYTIME YOU ARE WORKING ON THE AIRPLANE OR ENGINE... but, we point to the information that one can obtain.. as the real reasion for obtaining and keeping one. It has a companion manual call the PARTS BREAKDOWN MANUAL and it is about the same thickness... 2 inches.. as the service manual... both are the best that we have seen for cessna... Ok.. enough of the manuals... back to the fuel system.. Ok.. the next item that needs to be checked if the injectors are clean and the lines are all flowing the same... is that little pot looking thing up on top of the engine... that looks like a spider body... it is the fuel distrubitor ... and it has a couple of parts that are suspect.. the diaphram.. which gets hard..because of time, heat and exposure to fuel... its rubber. and we all know what happens to rubber over time.. it doesn't move as far...when it gets stiff... and then their is a fine mess screen that traps all kinds of dirt before it can get to the injectors... and they get dirty over time... if your not a mechanic you can not open it.. it is safety wired and sealed for a good reasion... as it is a technical item that requires the tech that knows... how to make it work...and test it before you go fly it... again... you have had your system checked and serviced in the last 5 years... or 500 hrs.. like the manual says... Ok... the next item is the fuel metering valve... better known as the idle adjustment mix screw... no I don't recomend that you mess with it either... unless you have a aero test box... or someone who is schooled in the fuel injection system... it is the device that regulates the fuel to air ratio...and you can get the whole system out of whack..(and possiably destroy the engine...) and it will then take a flow bench to get it back in balance... And the last item is the fuel pump.. The heart of the system... and it has two regulator adjustments.. vapor recovery jet.. bypass valve.. etc. The fuel pump and its regulators maintain a linear fuel pressure vs. RPM.. at a specific flow rate... again I don't recomend that you mess with this...either as it takes a sensistive gauge to adjust it.. correctly... and they are expensive.. 1300 bucks... and it get frustrating trying to balance the two adjustments...even for our techs sometimes... and it takes a real good one to get it right even with the aero test box or a flow bench... but, you can do a simple test... to check it... providing the rest of the system is operating properly... injectors flowing and all... and the test is real simple... to do everytime you take off... watch for the fuel flow/pressure guage.. to go to red line each and every time you go to max RPM... take off power...as your rolling down the runway... if it goes over or under your system may not be set right... if the pump is failing... it will not make the pressure/flow. If it goes high.. before achiving full RPM... the system is not correct... the needle should be pointing right at red line... 18 lbs for normal asperated engines... check the POH for the correct reading... and flow rate... So about the only item that is field repairable is the cleaning of the injectors... which incidently are at the root of the problem almost 90 per cent of the time... Hope this helps... G.M>
GMAS added later
Turbo engines have a aditional part to keep them producing power when they climb up in altitude...and operate under boost pressure... and the main differance between the turbo system and normal asperated engine is the high flow regulator in the fuel pump... which replaces the needle valve with a diaphram (turbo pressure ) sensitive bellows... The fuel distrubitor is not vented to the atmo... and is conected to the deck pressure...also to keep everything relative...(turbo pressure) and the injectors air input are also conected to the deck pressure line instead of the atmo..unlike in the normal aspreated engines... (turbo pressure) to keep the air flowing in with the fuel... otherwise the turbo boost pressure at the intake valve where the injector is located would blow everything back out to the atmo if the injector were vented to the atmo.... otherwise the systems operate almost the same... in principal... again the service manual has great diagrams showing the two systems...in color pictures... hope this helps.. G.M>
Paul Sharp then asked
I read over the information you posted. Thanks very much for it.
I do have both the service manual and the parts manual for my bird. I provide them to the mechanics when they work on it. Some two months ago, which is some 3 months after the last annual, I asked them to check the fuel flow adjustments on the front engine, and that's when I noticed the changes. The front was always a little off from the rear, but now it's worse. These are good mechanics, so I'm not going to jump to any conclusions, and they also maintain a fleet of Piper Seneca II's, which have the very same engine and are also turbo'd, so they should know it fairly well.
What is the little adjustment on the end of the little part that sticks out just behind the prop? That has been adjusted (a screw adjustment with a locking nut - easily accessible).
GMAS 337Skymasters Club replied
Paul... it is the low pressure fuel adjustment screw... it sets the spring pressure for the diaphram. If you look in your service manual you will see a drawing of the fuel pump... and on the end that sticks out away from the crankcase... you will see the diaphram that sets the low pressure fuel... The bolt/screw that goes into the pump.. that has the lock nut... increases or decreases the fuel pressure... when you are idleing to around 1800 rpm. The manual says that it should be set at around 5-7 lbs... at idle.. 650 rpm...and will maintain this pressure by controling a hat valve... when the valve is open it sends the fuel back around into the intake of the pump well ie. it becomes a bypass pressure regulator... now when we get the fire lit and the engine goes up to high rpm... the pump has the second adjustment.. for the high end... it is a needle valve in the normal asperated engines.. and is controled by the diaphram bellows unit... for the turbo... That little diaphram adjustment is kinda improtant as it sets the stage and is the building block for all other pressure adjustments... if it fails... the engine will not produce any power... it will just almost allow the engine to idle...but... will run real lean... as no pressure will make it up to the rest of the system... as the fuel will just circulate internally in the pump...
Thus the reasion I say not to mess with it until you can have the mechanic set the system up... to dink around with it... is to invite the insurance man to dinner...to explane why you landed in that bog... and lost the airplane.... I think I would take it back to them and let them know that it is not adjusted right... they will then put the gauges back on and set it again... now you know why Cont engine wants you to have the system checked each 100 hrs... it does change with time and age... and seasions.
Most happy to hear that you have the manuals... it is rare to find people who do... and it seems that the manuals are in demand... so make sure that you put a leash on them... as they will disapear... paper is no longer used.. and micro film is all that is left... so we have been led to believe The manuals are invaluable to the mantance and proper care of the airplane.
Your not the only one that asks about the fuel system though... had another today... who wanted to know what the little thingiee on the top of the engine... and should it squart..gas out of the little hole on one side.. "did they build it that way..." smile lucky guy.... he hasn't set the plane on fire yet...
Glad to have helped... G.M>
Paul Sharp asked further
Are you saying that the "low pressure" adjustment I asked about is also the "diaphragm bellows unit" for my turbo model? I.e., the normally- aspirated engine has a needle valve for the "second" adjustment, but mine uses this one adjustment for both? I do remember that when the engine was overhauled (last November), the guy adjusted this screw I asked about when the fuel flow overall wasn't up to snuff at cruise and takeoff throttle settings, and it affected how high the fuel pressure read at full throttle settings during takeoff, even though it's the "low pressure" adjustment.
Later he added
I guess one other thing that started me wondering about all this is not only does the front engine seem to read low now, the rear engine takes more fuel to get the proper leaning, per the CHT temp gauge, i.e., to get 125 degrees rich of peak. It is now reading 16 GPH where it used to read about 14.5 to 15 GPH. No adjustments have been made to it recently so I'm wondering what brought about the change. As for the front, as I have mentioned in the previous messages in this thread, it is reading lower than usual at cruise, although it reads the same to get the proper mixture - but it needs full rich setting of the knob to do it at 75% cruise settings.
So I'm concerned about why the front now takes full mixture settings and reads lower than it used to, as I have been mentioning, and I am also wondering why the rear takes more of a rich setting to get the 125 degrees than it used to about 2 months ago.
GMAS 337Skymasters Club replied
No... the low pressure diaphram is the one that has the screw with the locknut on the end away from the drive.. up into the crankcase... however their is a large blug casting toward the rear away from the prop.. on your fuel pump which houses the bellows unit that controls the high end pressure...it too has a an adjustment screw.... but is located at the end of the bellows unit... they both are set independ of each other but, work togeather... It sounds like the front engine is having problems with the fuel pump... or is getting out of adjustment... Cont. eng has a SID out... that they now want you to have it checked each year... at your annual... and we are finding that most of the systems on the turbos... are not within specs.... but, the deck pressure, controllers waist gates etc... all are part of the whole system.. and needs to be checked in total... as to the rear... engine... we discussed this before...
Paul Sharp finished off by saying
OK. Thanks for all the input. The mechanics are going to check the front engine's fuel flows, adjustments, etc. tomorrow. I appreciate your help.
GMAS>337 Skymasters Club replied
Lots of thoughts here.. but the most common one is the gear selonds... and the pump pressure switch.. and/or the contactor.. check the contactor by going around it with a good piece of stiff wire.. No 10 or better.. if it re-starts the pump.. replace the contactor... its the one inside on the nose wheel well.. next to the co-pilot... left foot.... next check the pressure swithch by jumping it too... don't worry the pressure relief will keep you from blowing the system and besides were only checking the switch for opp.. if you have a volt meter you could use it instead of the wire trick... and if the switch is open you will read 24 volts or better.. if closed.. it will be almost 0.... same for the contactor.. measure the voltage at the pump motor... to see if it is being toggled on and off... or if it is bad... check the hydralics to make sure you have enough fluid.. and that their is no leaks when done with that.. time to check the gear sel's by taking the tops off and cleaning them as the service manual says... don't use.. and death to all that do... alchol... use stodard solvent...to clean the plungers... use a small magnet to remove them after the top is off... and clean.. yes they do leake a little 5606 ... it keeps the o rings lubed... don't worry... per manual ... clean barrel with a q tip dipped in solvent and only most...not ringing wet.. swich around and swabb the inside of the barrel of the sel's... dry with air.. and replace plunger and cover... safety wire screws with... .020 or copper wire smaller than 032... why copper.. because you may need to remove them in flight someday.. and the copper is easier to cut.. with the screwdriver... we explaned theis in the club meeting.. last time... under emergencies in flight... Re-test and see if it works per manual.. if not.. things get more serious ... but, you did the right thing by getting it up on jacks until you find the grimlin.... hope this helps.. G.M>
Glenn Wood then asked
Could you give me a summary of the How's & Why's regarding the need to get to the gear switchs in flight.
GMAS 337Skymasters Club replied
No not the gear switches but the gear solenods ... as they control the gear movement.... From 73 on.. the one on the pilots side controls the gear down...when energized... and if it gets stuck down because of the oil as it gets old... it gets sticky... the gear will not come up... the one on the co-pilots side... is enerigized when the gear is up... i.e it is depressed... now if in flight the coil cools because of the rush of air... etc.. guess what would happen to the oil... yep it gets like glue... and that is why cessna wants you to clean the solenods every so often.. per their service book... if you dont.. you can run the risk of having the gear hang up... and without the valve being depressed.. you ain't going to get the gear to come down... even hand pumping..it.. so what to do... take your safety knife...you do carry a survival knife in your plane don't you... and punch a hole in the plastic at the base of the pedistal... and remove the plastic that is around the solenode area... take your screwdriver.. and break the screws loose (why we use copper wire) and remove... the top... take a pen/pencil what ever.. and find the plunger that is stuck ... push down on the pilot side one while putting the gear handle in the down position... and when the pump comes on the gear will go down... now we recomend that you use copper safety wire.. or copper wire.. for the safetying of these screws because when you exert a force on the screw head..it will break the wire easily... stanless steel will not.. and you have to use wire cutters to break it... One last thing that we have been told by others... who have had this situation happen... is that they turned on the heater.. and got the airplane as hot as they could... and it seemed to cause the old 5606 sticky oil to un stick... but, this is rare... I have only had 3 or 4 cases of gear hanging up...because of them in the years of my experance with the 337... and after cessna came out with the modified ones.. that they wanted the old ones replaced with.... so you can service them... the sol's have not been a problem but rather the switches and.... hoses.. which people never seem to get the message to replace the hoses... and one burst or starts leaking...on that last gear cycle... in flight.. they mess up the 70,000 dollar airplane because of a 10 buck hose... They do get old... and the book says to replace them every 5 years.. and yet we still see 73-78 skymasters with factory rubber hoses .... which are hard as rocks... Now think the insurance company is going to pay for the plane when the owner has not complied with the maintance....(smile) read you insurance papers.. their is a clause in it saying you will maintain it to .... and failure to do this will result in non-payment for damages incured....ouch... We have seen this clause used on several members... and they were left holding the bag for the repairs... it is like flying with no insurance... and the insurance investigator who usually is a real sharp mechanic also... knows what he is looking for.. in a old hose..hardness and the date on it... over 5 years and he goes away whistling... because the insurance company is off the hook... yes they do look... and after the accident.. the club can't do anything for ya... its too late.. so check them hoses... and only replace with what the factory authorizes.......... as a change to non factory materials..will also get you... you must maintain the airplane to.... FACTORY SPECIFICATIONS... not the latest craze... for your insurance to be in effect... Skysmith should really jump in here and fill you in.. as he sells insurance... and speaks more as an expert on the subject... than I... you might want to ask him to write a little about the subject here... as most owner/pilots are not up on how insurance companies work... hopes this helps.. G>M>
Scott "Sky" Smith replied
No the French really isn't any heavier duty.
I tried this on my 1970 Model E and nothing happened with either engine running. The book mentions no throtle settings. An A&P said that you may need to have the pumps running at or above a certain speed. but are the pumps strong enough to pull the gear up from under the plane if the engine speed is to high.
The manual systems worked correctly during the 100 hour inspection when the plane was jacked up and in flight the gear works fine, but are both pumps working.
Has anyone tried this test on there Skymaster and can give me a hint to what I an doing wrong. Thank you
Jason Friesen replied You might want to try the test again but place the gear selector in the down position (as opposed to down neutral) to start the flow of hydraulic fluid. I could be wrong here but I seem to remember having to do that in an old D model that I used to fly (It only had one pump but the test was the same).
Michael Hayes replied
I have a 1970 337 model E and replaced both sides of the panel, actual I changed from black to white - grey to lighten up the in sides. The company I did business is Kinzie Industries Inc. P.O Box 847, Alva Oklahoma 73717 Phone # 405-327-1565 Fax 405-327-0526 They have a book that covers many years and models of cessna. There E-mail address; KinzieAlva@aol.com I have found there part are just a little thicker than the material used by cessna.
Good Luck - Michael Hayes
Carlos R. Hernandez added
Try Kinzie at KinzieAlva@aol.com for plastics. Pacific Coast Avionics and Gulf Coast Avionics and may others have a Light wedges and UMA Lights that fit between the intrument and the panel have not tried them but if you do tell me about it. I´m redesing the panel. Pleasure, Carlos
Paul Sharp replied
I don't know about the way they're mounted in your plane, but I wanted to comment that I have one dimmer potentiometer that's bad, and when I priced them they were around 110 bucks. Since it's the compass light dimmer I haven't worried about it yet, but I thought that was awful high for a dimmer pot.
G.M>337 Skymasters Club also replied by saying
Hmmmm... if I were you ... I wouldn't go to that mechanic... he doesn't want to do the work... to get the pannel loose... the switches you talk about are just snaped in... they have two plastic ears and when pressed togeather push out... now as to the pot itself... they are standard old potter/blumfied type... A or B's if my memory serve me right... and if you hold your eybrows just right you will not have to take the pannel off.. as it seems that the thing will hold the nut in place and you can unscrew the pot off the back... being careful of course... and removing the wires first... and when you put the new one in... you want to not solder the ground wire .... located on one of the terminals of the pot to the back of the case... instead take it to a nice place on the control yoke housing... and ground it to the frame... to keep from having the flickering light problem... The other pot can be removed by undoing the extention cage and removing it from the rear too... just behind where the slide switch is located... and again they are just simply good old electronic parts... that can be gotten from a distrubitor... for about 8 bucks each.. the last time I bought some... however radio shack does not sell them... sorry you have to go to a electronic parts store or else call ohmite or potter and ask where one can get one... the numbers on the back are the electronic part not cessnas... hope this helps... fly safe.. G.M. 337skymasters club
Gerd Wengler also added
I have a 1976 337G with the gear mod. My experience is only positive. If you have the money, it is worth every penny!
later Gmas 337 Club added
Had a interesting call today.. seems that a skymaster was flying from Arizona to the bay
area ... and the weather here has been nasty.. cold and frozen in the morning... the
freezing level is quit low... and it seems this fellow managed to find some of that nice
snow and ice while he was enroute to the west... and he had the gear mod done on his
skymaster... yep you guessed it... the stuff got into the area where the mains were and
froze them solid in the wells... He had his cell phone and just so happened to catch us at
the club phone. "What can I do... he asked... and I was thinking... put the doors back
on... but, that wouldn't get him out of his problem... so I though of jimmy stuart in the
movie... the sprit... and told the fellow to go west... drop down over the ocean... when
he got clear of the coast and fly below the freezing level... else go high and then put the
gear down before coming back through the moisture... he elected to fly out over the
ocean and after about an hour.. he called back and said that he got the gear down.. and
landed... Lesson to be learned... leave the gear doors on.. and don't make more holes in
the airplane... on the ones that we've seen that have had the mod.. done we see lots of
mud, dirt, and all kinds of debree in where the mains tuck..up.. not to say that the other
won't get dirty.. but it seems that when the doors open they kinda vacuum the wells
out... and keep them a little cleaner... of course if you take off in wet conditions... I
would leave the gear out to dry... so to say... as then when you tuck them up the stand
less of a chance of freezing in the wells.. as the drains are usually already frozen over...
Fly Safe.. G.M> 337Skymasters Club.
In a message on another topic GM 337 Club... said the following about the landing gear (This was not connected to the above messages.)
The original main gear was powered by a single actuator.. later it was changed to a dual no coupling... each leg has its own actuator.
Dave Zavoina replied
Try recycling the 5 amp circuit breaker--they get old too, takes electricity to close the doors
Mike Swagerty added
I had the same problem on my two-ten. The problem was a broken wire from a micro switch on the gear handle to the solonoid which operates the gear doors. Like the fellow said, "takes electricity to close the doors."
skymaster740M also added
I had the same problem which was caused by a defective power-pack switch (part 16-4042) and switch actuator (76-1200). The parts are less than $25.00. I believe the switch supplies power to the gear door solenoid after the gear is either up or down and locked.
Michael Hayes replied
Cessena 300 series $6000 Devine Airport, Texas 800-663-6070 www.devine-air-group.com
Thanks, Arizona folks were quoting $9000 which felt overpriced like a lux car.
GM @337 Club replied
Dick... we had a member at the club reciently go through the same problem... and he never found the seats... but, made a combo 5/6 seat that was real neet for the back ... it velco'd down and attached to the back wall at the tiedown locations... as two pieces... it was quite simple and as it seems to me didn't cost much more than some alu, wood, foam and the material to cove it with... that seems to be the only way you are going to get by "reasonably " Hope this helps... if you need more info... let me know and I will see if he has his plans still... I know he got a one time field approval and 337 on it...G.M>
James Young replied
Try this guy. Don Nieser Commodore Aerospace Corp. 405-722-4079
GM 337 Club... replied
Makes no differance to what year you have... they all are under the AD for rear main spar inspection. It comes from the attachment point for the booms which intersect at the rear spar location. At 3000 hrs and thereafter at intervals... they want you to look at the spar box section in this area and check for cracking... I have never seen one crack as yet but, the original AD was written because we believe when they were used in the military and rated for 6000 lbs.. and were flown almost like they were aerobatic... that this check came out. We have found that the airfraim is so overbuilt that it should last a good long time If you will note the AD's on them are few.... the ones that are ...are common to all cessnas... one of the most important for the 337 is the attachment section... where the strut attach to the main spar in the wing area... here corrision is the problem... and seems to be the worst thing about the airframe... but, this is atribuited to its age and care.. Structurally it is one of the strongest that cessna made.
Gerd Wengler added
I see that the "GM 337 Club" send an answer to your question; however that answer is incorrect. The AD is 78-09-05. It is to be complied with for virtually all Skymasters (not only older ones). The compliance times are as follows:
(1) For Non-pressurized models 5,000 hours and then every 500 hours. (2) For Pressurized models 10,000 hours and then every 500 hours.
The 3,000 hours mentioned apply only "For those airplanes which have engaged in contour or terrain following operations at low altitudes, such as power/pipeline patrol, fish or game spotting, arial applications, police patrol, live-stock management, etc."
So if you want to purchase a Skymaster close to 3,000 hours, make sure you know its past history. A good source to find all applicable ADs is the Transport Canada website http://www.tc.gc.ca/AD/ad_e.htm
Gerd
GM 337 Club... added
I would still have the spar checked at 3000 hrs... and stand by it.... The AD as cited is correct... however... the airplane cant read... and the time listed is too long between inspections... So if you value your Butt... I would go back to the 3000 hrs inspection and from their check. Now some people will go by the book... because they usually don't have first hand experance... they own a model that is hardly flown.. or keep it hangared... and use it for a status symbol... or what ever... but... in the real world.... of flying it has been our experance that at or around 3000 hrs.. we have seen several that were "babied airplanes" and those had the beginings of cracks... and while your at it... Gerd should have mentioned the main spar strut attachment point... here we are looking for corrision.... Which is covered in an earlier AD/SB... Now as to Now.. as to Gerd's advice or correction... He can recite the AD and say I was incorrect if he wants... he probably doesn't fly so.. it won't be his butt that hits the ground... Again The airplane cant read.. so A/D came out because we were finding cracks in the back spar attachment point... and as the "OLDER" mixmaster metal gets harder with age... it appears that it gets more brittle and cracks easier.. (smile) So to protect your bottom's.. I suggest the 3000 hr. inspection... if not more frequently... as the boom sections puts almost all the stress on this point... when in flight ... Now gerd can tell you about the elevator trim tab and a thing called boom bounce... in flight... and how it effects this area. Please write a little about topic of interest on this for all of us Gerd.... and how it could/does relates to rear spar cracking SO because we have the AD showing up in 78 you could assume that it should be checked on all models (Last one manufactured in 78) But, in the real world.. The later ones are the youngerster of the fleet and are still plyable... with most of them having under 2000 hrs... The Club and I still stand on the 3000 hr... inspection time.. for safety sake...
GM @337 Club replied
Bob... This is a difficult one... we have contacted our sources at Cessna... and they promass to get back to us ASAP... they did need more detail as to which spar fwd or rear... and exactly where it is occuring... If you have any further info.. would help. They suggested that a cleaning of the area... and using a die penatrent test be preformed to see how long a crack is showing up.. ... and making sure it is not a machiening mark... or scratch... that could have been their from assembly... It is of interest to our club too.. hope this helps g.M> 337 skymasters.
Bob Attwater added further
GM ... i now have some additioanl details as sent by my maintenance organisation to Cessna. I showed your initial response to my engineer and he confirmed that the crack was real and confirmed. He has written to Cessna as follows : "that during inspection according to cessna Service Letter ME78-2 a crack was found in the RH spar web and RH rear spar web. He requested the relevant repair scheme or precedure, and requested price and availability of the following items, being RH front spar 1422500-7 (E) Web inboard 1544502-3 (D) RH rear doubler 1422514-2 RH doubler web 1522025-2 He also noted that he believed that new parts for later models are redesigned, and no longer had this problem, and did not require further inspection."
Cessna replied that these part numbers are no longer available from Cessna. While they could be made, an order would have to be placed before any pricing or supply could be determined. Cessna made no comment about any later design of these parts.
Is there any other specific information that i could supply that may be of some use to you in responding ?
Looking forward to your continuing assisitance, Regards, Bob Attwater.
Dave Zavoina replied
All Skymasters have wing struts. The wing/boom/tail assy's are too heavy to be cantilleviered out there. Plus all of the surface control cables except for the aileron balance cable pass through one or another of the lift struts.
GMAS 337Skymasters Club replied
yes cessna did have the strut farings... and they are made out of plastic... and no they are not like the 182 or any other cessna compatable ones... the 337 has one of the lonely ones... as of this time I know of no other manufacture that makes them... sorry... and cessna thinks highly of their parts... so save lots of money... G.M>
GMAS 337Skymasters Club replied
the syncrophaser are not hard to come by... most of the people.. who have them say they do not work anyway... and use the old ... grab the rear engine prop control and move till the droneing stops... but if you just have to have one... I am sure that you can get one through white ind salvage yard or one of the local wrecking yards... they don't have to be just for the skymaster... the remote one ... which model no excapes me.. for the moment is also used on the other cessna twins... the price... I would expect that you will pay around 200 bucks for one... but, like I say.. they probably removed it for maintance and repair... and forgot about it... you could check back and see where the plane was serviced... and ask them about it... you would be surprised... to find that some of the shops store things like this in some attic or in storage... as their is not a high demand for them... if you bought the plane reciently... go back to the seller and explane that you didn't get a complete plane... and want the rest of the pieces... a good reasion to have the airplane surveyed independently... before you buy...as they usually report what is missing and what is working... hope this helps..G.M>
Mike Zinn added
Just to give you encouragement. I've had the synch working most of the time in my 79 P337, and I love it. It does an amazing job of smoothing out the noise and vibration, and the adjustment to the pitch gets the rest of the annoying drone dealt with. A great comfort enhancer. Well worth the effort.
Both prop governors need to be in good condition, and tight in terms of the linkages. I've had the brain tweaked once five years ago, then again now (in process).
Michael Hayes replied
There is a company that makes wing tips for 337. I have them on my 1970 Skymaster. The company is Norton Inc. Wellington, Kanas 67152 Tel. # 1-800-835-2051 or 316-326-2241. Remember they do add length to the wings and a 337 is over 38 feet to start with. Good luck