Aft Wing Strut Problem and Stall Speeds

[FlyingGourmet]

While Removing my wings to get at my fuel tanks I discoverd a problem with my aft wing strut. The adjustment screw in the end of the Aft, left wing strut appears to have been modified. It has course threads compared to the one on the right wing. It appears as if someone stripped the threads of the old adjustment screw way back when -then re-tapped the end of the strut (probably weakening the strut) and replacing the adjustment screw with a course threaded bolt that had a hole drilled through the middle and the end cut off to adjust the wash in the wing. My Mechanic Gasped at the idea someone would do such a thing. He was one of the mechanic's at Wipaire when they did the testing for the gross weight increase for the Super Cubs and said that was one of the first areas that would fail while being stressed.

Is there any way to strengthen the existing strut, or will it simply have to be replaced? Another T-crafter on the field had two struts he was willing to give me. He got them from somewhere and was successfull in robbing one adjustment screw while the other stayed put. In his attempt to remove the screws he heated the strut ends with a torch -did this effort junk the struts?

Finally, My T-craft is the only T-craft I've ever flown. I thought it flew a little fast and was pretty unstable at slower airspeeds. This was verified by a friend who owned 3 T-Crafts, one with a 65 and two with 85's. He said "She sure is a ripper, but really dosn't like to slow down." It stalls around 50 mph with just me and full fuel. Just for kicks I had the airspeed ind. tested (however not with a certified tester) and it checked o.k. Also the the adjustment screws on the wings were bottomed out. Any suggestions. I have the Model 19 stc w/ 0-200. This concerns me because to stay out of the yellow arc I have to pull back to 2100rpms all the time. It frequently indicates 117-120 mph at a setting of 2400. Manuvering speed dosn't feel like it should and I would like to utilized max short field capabilities. Therefore my main questions are: Is this typical behavior of other 0-200 long mount conversions? Can I further improve its slow flight capabilities?

Thanks again,
Nick

[dedrekon]

Re: Aft Wing Strut Problem and Stall Speeds

The cruise speed is in the right range, maybe a little fast, but every Taylorcraft is different. The stall speed is off. It should stall like any other Taylorcraft which is in the high 30's. Weight could be a factor.....if you're always flying at 1500 pounds instead of the BC12D's 1200 pounds, that would certainly raise the stall speed, but probably not to 50. In my F19 conversion stall speed at gross is in the low 40's.
Most likely your bird is either very heavy or rigged wrong....or both.

Vincent

[Dano"T"]

Re: Aft Wing Strut Problem and Stall Speeds

I indicate 108 at 2400 on my C85 1280 gross T-Craft and stall is 40 when moderatley loaded. I recently changed props so I'm a little slower now (95 floats)...I put a 74-40 on....I had a 72-44. It's good that you are getting to the bottom of this now....your problem could easily get you into trouble if you were heavy and stability problems occured.....have you done an accurate weight and balance? it would be worth checking....that could cause some problems as well. Aft CG?

[Dusty]

Re: Aft Wing Strut Problem and Stall Speeds

Interesting - my 840 lb C-90/O-200 T-cart stalls somewhere around 50 as well. Maybe closer to 45, but it's falling out of the sky while the Champ is still flying.

Stalls are a little more intesting than the Champ, but nothing that I'd consider unusual.

I'm running a 74/40 prop, and no amount of dragging her in will get the stall speed much below that. I can get the AOA up so the airspeed indicator slows down, but a GPS will confirm that she don't fly much over 45.

I've had a dead moose in it, so the CG ranges - and I mean all of them - have all been empirically tested with no ill effects. She might have been flown _close_ to gross a couple of times. It's not a Champ or Cub, but seems to handle the weight just fine.

Everything seems the same as any other small plane, except she stalls faster. I always assumed 40 was the book number and 45-50 was just reality with the goofy wing. Asking for real-world opinions: Do T-carts really stall that slow? How do they compare with a Champ or Cub?

So, where do we look? What's rigged wrong? Dropping the stall a few MPH might make me slightly less anxious to get this thing sold....

[Dano"T"]

Re: Aft Wing Strut Problem and Stall Speeds

My E.W. is 824 so that isn't much different....and my stall is a mush not a hard break and it usually occurs just as the airspeed hits 40...and I have a brand new calibrated a/s indicator....gps confirms all of this. I fly my approaches at 55 usually....50 if I'm going into a short strip. If I'm alone with only 4 or 5 gals of gas...I think it stalls closer to 36 or 38. The C90 T-Craft me and dad just bought is the same....with a slightly harder break on stall....not much though.

[Dano"T"]

Re: Aft Wing Strut Problem and Stall Speeds

Dusty,

THIS is me in March landing our C90 T-Craft on a windless day with me (200lbs) and a passenger (250lbs) aboard...aproach 50 mph....touchdown about 38. You can see that it touches down slow...and we were fairly heavy, this T-Craft weighs 832 empty. I had 8 gals in the nose and 3 or 4 in the right wing tank.

[FlyingGourmet]

Re: Aft Wing Strut Problem and Stall Speeds

The cruise speed is in the right range, maybe a little fast, but every Taylorcraft is different. The stall speed is off. It should stall like any other Taylorcraft which is in the high 30's. Weight could be a factor.....if you're always flying at 1500 pounds instead of the BC12D's 1200 pounds, that would certainly raise the stall speed, but probably not to 50. In my F19 conversion stall speed at gross is in the low 40's.
Most likely your bird is either very heavy or rigged wrong....or both.

Vincent

I really would like to find the High 30's low 40's. Acording to my Wt/ Bal (Which I plan to redo for verification) claims my Empty weight is 836 -even w/ full electric. As far as rigging -the the adjustment screws are bottomed out in the aft struts to give the max ?angle of incidence?. Is there anything else that can be done? -I am going to do a new wt. and bal. and verify where the C.G. is, but I'm pretty sure it's forward if anything. On paper with full fuel and two 180lbs I'm at 1400lbs. Prop is 69/48.

Vincent, I'm jealous of your plane's performance.

[FlyingGourmet]

Re: Aft Wing Strut Problem and Stall Speeds

I'm running a 74/40 prop, and no amount of dragging her in will get the stall speed much below that.

What do you get for static RPM's prior to take-off? How much take off roll do you use with yourself and full fuel on a calm day? -I'm considering a bigger prop.

Dan -what do you get for static Rpm's on the water with your bigger prop -Also, did you use your other prop while on floats to compare perf?

[Mark Julicher]

Re: Aft Wing Strut Problem and Stall Speeds

...approach 50 mph....touchdown about 38....

Hey no fair quoting stall speed in ground effect!

[Dusty]

Re: Aft Wing Strut Problem and Stall Speeds

Now I'm even more confused. My touchdown deck angle is steeper than that, even without power (which I almost never do). My tailwheel always hits long before my mains (or I bounce), even with my big tires. On skis, trying to land short, I usually hook the tailwheel and drop a foot or so onto the mains. It also _looks_ like you fly a much faster approach than I do (deck angle and the lots-of-float are my clues).

So, anyone, what should I and FG check to see if the issue is rigging?

[Dano"T"]

Re: Aft Wing Strut Problem and Stall Speeds

That approach was 50 mph with a little slip over some power lines which are hard to see behind the little barn. You said your stall speed is 50. I fly my approach at 50 to 55. Maybe it looked faster because of the slip, but that was a 1000' strip and the wind sock pole is 200' from the end of the runway. It is hard to see in the video but the approch is over a road and some powerlines. I ocassionally hit tailwheel first if I come in with a little bit of power which causes a slightly higher AOA at touchdown.

[Dusty]

Re: Aft Wing Strut Problem and Stall Speeds

Nick - I get something just under 2500 on the ground. I can't redline it in S&L flight (maybe I could with small tires??).

Takeoff is pretty impressive. I can get off in _just_ more distance than the Champ, but I'm of course going way faster when I leave the ground. On a good surface, on wheels, light, probably 250' takeoff. Of course, no way I can land in that on wheels with those wonderful T-cart turn-assisters (I hate to call them "brakes").

The static thrust is amazing- way better than the Champ. The Champ has a 115HP turning a 74/42 Sensenich, T-cart has C-90 turning a 74/40 Mac, but the Tcart is 100lbs lighter. I think my next prop for the Champ will be a Mac, in the off chance that's the difference.

It's a great plane in overflow.



I dropped through, got stuck, got out and busted the ice in front of the gear legs, fired up and drove out. My knees got wet, and of course there was a foot or so of snow on top. In the Champ, this is the first step to a long night of "winter camping". By the way, she flies just fine with 50lbs hanging off the tailwheel.

Dano - whatever your ASI says, that's pretty fast. I've watched it about 1000 times now - THANKS a BUNCH for the link. I have to get a video camera - I've learned a lot watching you, (like watching a friend land, but with rewind!) I bet I could learn even more watching me.

So, nobody here knows how to check my rigging? Any wild guesses? Something I can beat on with a hammer??

[Dano"T"]

Re: Aft Wing Strut Problem and Stall Speeds

Dusty,

You are right....I thought about that day last night and then I remembered telling my passenger that since we were heavy I'd bring her in at 60 and I even gained just a little in the slip but I figured since My 200 lb butt and his 250 lb but were in there I'd setttle with plenty of room. I used almost half of that 1000' strip on that landing. I just had a brain fart and forgot telling him that we were using a faster approach speed. HERE is me earlier in the year landing my 85HP T-Craft from the other direction.....Too far away to see but i plunked this landing in slower.....tail first like you said you do it.....this one was a 50mph approach with a little bit of power. HERE is the takeoff

[VictorBravo]

Re: Aft Wing Strut Problem and Stall Speeds

Dano, when you do approach at 50 mph, how much lift reserve do you have for the flare? On my airplane, a 50 or 55 mph IAS approach doesn't leave a whole lot in it. If I get a lull or low altitude shear or a gust at a critical monent, the speed decays to the point where I may not have enough to arrest the descent rate. In still air this might not happen, but i haven't seen still air in a long time.

[Dano"T"]

Re: Aft Wing Strut Problem and Stall Speeds

I never do it without a little power.....it gives enough thrust over the controls to make them effective in case a wind gust grabs you....you need to be on the throttle though....like dusty said...usually your tailwheel will hit first then the mains....it will stick it in short. The higher AOA increases the sink rate considerably or at least makes it steeper. I only do this when landing on really short strips. If you watch the landing (the far away one) closley in the video you can see a wind gust grab me and you'll hear the motor rev up a little. The reason they all cheered was I guess I was the first one to land at the new strip....on skis at least. Or....Maybe they were having a long winter. The owner is a new Student pilot and he rebuilt a really nice Cheif with an O-200....I was taking him up and giving him the basics of ski flying.