Hello to all, Im very proud to join your group!

[scottygofast]

Ed & Karl, thanks for the welcome~

Thanks for the info on the trim, after looking at the POH, I went to the airport today, and found that with the master on, and flaps retracted, the maximum trim nose up is at the bottom of the white take off mark on the trim wheel. I then dropped the flaps incrementally, and found that the trim wheel, even at full flaps down, would not trim any further nose up than the spot it was at with flaps fully retracted. Would that mean that there is a circuit or something not closing when the flaps are operated, or would this be more of a cable rigging issue? I only ask, knowing from your response that its a mechanical linkage, because it didnt change anything at all with the flaps operating. Also, before I took it up on the maint. flight friday, I noticed while taxiing that the elevator was catching, or had a tight spot halfway or so through its travel, I had the mechs check it before we went, and they had found that the chain that drives the nav-o-matic had a kink in it, so they tightened the chain and the problem was resolved.

How much nose up trim, in relation to the take off white marking on the trim wheel assby, would you say you have in the elevator while on a normal approach to landing? obviously, if theres 16deg. of travel im not getting out of the trim tab, would be the reason the airplane feels so "heavy" on landing, wouldnt you agree?

This is a very cool and unique aircraft, that im looking forward to putting a lot of time on, and I totally agree with you Ed. Im studyin~

Thanks again for your time~

[hharney]

For take-off I use the bottom of the white mark (up trim) with the published 1/3 flaps. I have the Horton Stol wing and normally rotate at 75 - 80 indicated although the aircraft is already asking to leap off the ground.

For landing I use 1/3 flaps on downwind (160 MPH) and then slow it to 140 MPH for the gear.
On base I use 2/3 flaps and final full flaps. While base to final I will use 110 - 120 MPH and full up trim. When I add full flaps on final then the trim system allows more up direction as desired. On final I use 100 - 105 and normally end up full up trim with full flaps. Once the runway is made then let it bleed to 75 or 80 for touchdown. I find if you land with too much speed you may experience some hard landings or maybe the "porpoising" you might be experiencing. Keep in mind with my numbers I have the Stol wing.

Yes the elevator is a little heavy but use the trim to assist and you will find that your landings will be greasers. The Skymaster is a very easy airplane to land.

[edasmus]

Hi Scotty,

I cannot answer your question precisely about where the exact trim location is for landing. I am fairly sure it is aft of the range marked on the trim panel next to the trim wheel. The no flap range is the range marked on the plastic panel next to the trim wheel and then the trim pointer actually moves aft of the entire range marking on the plastic after I have selected full flaps for landing and select more aft trim to relieve the heavy feel of the elevator. After landing and selecting flaps up, the trim wheel will automatically roll itself forward to the aft end of the range marked on the plastic panel which is the full aft location available with the flaps up. As I mentioned, on my airplane, this is all accomplished with mechanical linkage. There is no electrical involved here. The next time I fly, I will pay close attention to the pointer for various stages of flight and report what I find. We are to get 6-10 inches of snow tomorrow so it may be a week or two before I get my hanger dug out enough to fly.

As Herb mentioned, these aircraft are very easy to land. My experience has been quite easy to land on the mains and hold the nose off with easy back pressure on the control wheel. It is not heavy in pitch at all if properly configured for landing. I'm not sure if all models of the 337 have this trim configuration. Have your shop check the service manual for your model. My guess is something is not rigged correctly in your airplane. I suspect you are working too hard to land your plane. I have never heard anyone describe it the way you do.

I do not know if you have any time in a Cherokee6, but that was a nose heavy airplane. I would actually roll enough aft trim on short final in that airplane to cause me to have to push slightly on the control wheel to hold the proper attitude. Then for the flare, the required back pressure was at a more manageable level. In my Skymaster however, this has never been the case. There has always been enough trim available and much better balanced control forces in all configurations to not have to work even remotely hard. I'm thinking you should have the control rigging checked. Good luck and I will report back with more precise trim positions when I can.

Take care,

Ed

[edasmus]

One other thing Scotty....with the flaps full down and the trim at the aft position on your trim pointer range, it actually takes more force to manually roll the trim aft for the additional amount available when the flaps are down on my airplane. Obviously, do not force anything, but the force to manually roll the trim the additional amount available aft with the flaps fully extended is definitely higher then rolling the trim through the normal range when the flaps are up. There is more resistance on the trim wheel is what I am trying to say. The level of resistance is high enough that the first time I attempted it after my IA re-rigged the trim system he had to demonstrate for me. I thought I had wheeled in full aft trim with the flaps down but in fact I had not. I hope this makes sense.

[edasmus]

Hey Scotty....

I checked my POH today and from Section 2 - Systems, page 2-14, the following is exactly as quoted in the POH.



WING FLAP-ELEVATOR TAB INTERCONNECT SYSTEM

"The wing flap system is mechanically interconnected with the elevator trim tab system to automatically eliminate excessive nose-up trim while the wing flaps are being retracted.

With the flaps retracted, the trim control wheel can be rotated in one direction until the trim position indicator reaches the NOSE DN position, or in the opposite direction until it reaches the lower half of the TAKE-OFF range marking for nose-up trim. As the flaps are extended, additional nose-up trim beyond the TAKE-OFF range can be utilized. Maximum nose-up trim is available when the flaps are fully extended. As the flaps are retracted, the interconnect will automatically rotate the trim back to the TAKE-OFF range."



Check your POH and see if you can find any reference to this system. What year and model do you have?

Ed

[edasmus]

Scotty,

I managed to do some flying over the weekend as well as today and here are my observations with the elevator trim. I place it in the center or maybe just a touch aft of center of the "TAKE-OFF" range marked on the pointer scale. This makes for a nice easy rotation as the airplane is accelerating through 85-90MPH with flaps at 1/3 extended position. After rotation a slight forward trim is required to hold 110-120MPH on initial climb. Once the airplane is cleaned up some additional forward trim is required to cruise climb between 140-150MPH. All speeds are indicated airspeeds.

During landing, after adding full flaps, the trim pointer is well aft of the "TAKE-OFF" range. Probably a third to half an inch aft of the "TAKE-OFF" range as marked. This is into the additional trim that becomes available with the addition of full flaps. This is at a final approach speed of 90MPH with full flaps making for an easy flare into a smooth touch down with the nose wheel clear of the runway. I can continue to easily hold the nose off for several seconds after main wheel touchdown until the speed bleeds off at which time the nose will gently fall to the runway.

Hopes this helps.

Take-care, Ed

[hharney]

If you remove the rich Corinthian plastic that Cessna used around the trim pointer you will see that the pointer can be moved and adjusted very easily. You may want to roll the trim to center (check the tab on the elevator) and be sure it is calibrated to about the top of the take-off mark.