Pre-war trim adjustment help please

[VictorBravo]

On the ferry flight home with my brand new 1940 BL-65, I noticed that the trim would spring back to a certain level at cruise. I'd try to push it down a little further to relieve forward pressure on the yoke, but it would spring back. I could trim it nose up for landing OK, but when I got into high speed cruise (94 blistering miles an hour), it just sprang back a bit. 1000 miles with a pound of forward pressure required on the yoke.....

I also noticed that there was some fairly large deflection of the trim vane, and this probably creates some extra drag we don't need.

Does anyone here know what or where to tighten this up so it has more friction?

Does anyone know if it is advisable / possible to simply enlarge the size of the trim vane by 10% so you get the same trim force with less deflection and drag? I know this would officially require some paperwork, but I also know that the field inspectors do not normally carry the pre-war T-craft trim vane drawings with them

Bill Berle

[M Jones]

Re: Pre-war trim adjustment help please

Hi Bill,

Does your BL have a pressure cowl, or open cowl? NC22606 originally had the open cowl, but was converted to a pressure cowl before I got it. I mention that because I'm told that the flipper trim on the pre-war models has less effectiveness with a pressure cowl. That may be the case, I haven't got any experience otherwise, but I also have seen similar behavior as you did. There's plenty of up trim authority at landing speeds, but not quite enough in cruise.

When the header tank is full, very little forward pressure is needed, but as the fuel burns off, a little more pressure is required to keep it from climbing. After the last flight long X/C to La Grange, I think my left arm is in much better shape than the right... (Just for fun, try leaning forward in level flight. You might be suprised how much the weight shift effects things!)

Check the trim lever pivot point directly under your seat. I tightened that up several years ago and haven't had the "spring back" problem either.

Good luck,

[Howard Wilson]

Re: Pre-war trim adjustment help please

Let's see, that's 5,280,000 foot pounds/thousand miles;-)
Bill, my experience with 20442 a '39 bl open cowl w/ a metal prop 74ck-2-36 is similar to Mike's. Flew it 1086 s.m. when I bought it, Fargo ND-Frederick MD. It flew hands off in smooth air with the trim lever in mid range. But with low fuel in the nose, a couple of pounds of clothes, cookies, charts, and tie down stuff in the baggage compartment, and your arm on the back of the seat (i always fly with my hand on the throttle.....) it will start for the moon, very subtle at first.
Darn near full down deflection needed at times.
I go to full up flipper deflection for landing and still have to hold a little back pressure for a good over the fence speed.
Wouldn't adding surface area just give you another kind of drag? Still need the same lifting force back there. Maybe a STC to put on a high aspect ratio flipper! I want 10% on the sales. It'll be good at keeping the grass cut too.
94 mph!!! what are you burning in that thing? I timed it across the section lines in the mid west and was consistently getting 81 -82 mph with neutral winds. Probably turning 2300 rpm. No bungee covers or landing gear to fuselage fairings.
Please post your T-craft travel stories. I remember reading your older ones when I was considering buying a Taylorcraft and you really caught the essence of this kind of flying.
(Nobody can beat Norm's stories when he's on a roll, but you come very close.) Howard

[taylorcraftbc65]

Re: Pre-war trim adjustment help please

Bill,
I routenely cruiuse at 90-95 in my 1940 BC-65, and don't have to fight the yoke, but only after I tried something that was suggested to me on this site in June of last year.

I was told to inspect the leather washers on either side of the trim actuating lever, and tighten the through bolt that held the lever in it's brackets. I looked under the seat, and lo and behold, there were no washers at all. ( I had commented on this site that I could not get the lever to "stay" even in the pattern).

I cut out a set of washers and installed them, and I can hold trim up to 100 indicated. She will do 105 flat out, but I have to hold several pounds forward stick at that speed to hold her level.

Hope this helps.