Author Topic: Lap times, increase line length or drop some pitch? (Read 2206 times)

Curare · « **on:** April 14, 2013, 11:02:19 PM »

Hey guys, I just finished a flapped plank 1/2a stunter (tee dee 049 powered), which is going great, but it is screwing me into the ground a little.

First flights were with a MA 6x3 and it was moving, even on 40' lines, but had great line tension.

I then dropped to APC 5.5x2.5 and the speed was more managable, but broke that prop pretty quickly.

I had a rummage in my flight box and pulled out a APC 6x2, and while the speed was nice and slow, I had no line tension at all. I was still able to wing over and do most maneuvres, it felt very light and didn't instill much confidence.

I've now found another 5.5x2.5 and will carry on with that, but now I"m thinking as to whether I should go for more pitch (maybe a cut down 6x3) and cut a new longer set of lines.

I'm currently running around 40' spider wire.

Thoughts?

Jim Thomerson · « **Reply #1 on:** April 15, 2013, 07:23:35 AM »

Back in the day, I flew TD 049 airplanes on Master Airscrew 6 x 3 cut down to 5.5, on 42 ft 008 lines. I never timed laps, but I could fly the pattern without stress. After a flew 1/2 A flights, the Fox 35 airplane seemed so slow and easy to fly.

Reptoid · « **Reply #2 on:** April 15, 2013, 07:10:27 PM »

Greg;
If you can find a black Cox 6-3 and cut it down to 5 1/2" it should slow it down a hair but retain good line tension.

Larry Renger · « **Reply #3 on:** April 15, 2013, 09:04:10 PM »

Hey, how about a photo and some specifications? I don't recall seeing a flapped plank stunter before.i

Curare · « **Reply #4 on:** April 15, 2013, 09:46:43 PM »

There are, if you get bored look up the "yardstick" and "stunt wind" Both are flapped plank wing stunters.

I started with similar moments to a white lightning, but decided I wanted flaps becuase my life isn't hard enough.

As it turns out it's a great little model. Span is 33" and I managed to jag the CG so it's about 25%. Considering the monstorous tail area I think you could almost run it back further!

Considering it's sort of become a reduced stunt wind, it's now nicknamed the stunt fart!

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john e. holliday · « **Reply #5 on:** April 16, 2013, 09:13:56 AM »

Hey I like it.

Paul Smith · « **Reply #6 on:** April 17, 2013, 07:09:59 PM »

The plane looks great.

In my experience, messing with props never slows a plane down as much as you think it should. The wrong prop might slow a Racer down from 90 to 84. But if a Stunter is going 60 you have heck of a time getting it to go slower with a different prop, short of completely killing the performance. Frequently, you have way too much pitch to start with and going to lower pitch actually makes it go faster.

Outthrust might slow the plane down somewhat with positive side effects.

Curare · « **Reply #7 on:** April 18, 2013, 08:58:46 PM »

Well after cracking the plane up for the 5th time I'm all out of APC props (you don't have time to think in 1/2a as I'm finding). I managed to get some time and cut down a set of MA 6x3's from 5" in 1/8" incriments up to 6". I'll try and deterimine what the best prop is for letting the engine unload, not overspeed the airframe and give some good line tension.

ray copeland · « **Reply #8 on:** April 19, 2013, 08:03:53 AM »

Plane looks nice, i like! Have you tried the cox 5x3 prop, believe it or not , sometimes it is the best choice. Keep up the reports , i would like to build one similar someday.

John Crocker · « **Reply #9 on:** April 19, 2013, 05:34:48 PM »

Good looking plane! What is the fuse length and thickness and what is the wing thickness?

Curare · « **Reply #10 on:** April 19, 2013, 11:56:27 PM »

Ray, I would if I had any left!

John, wing is 1/8" medium sheet, and the fuselage is a little over 3/16 (5mm here in aus).

It's a bit wobbly, but it's light:D

If I do another I'll probably wedge a peice of 1/8" x 1/32" carbon in between the sheets to act as a spar. I'm also tempted to fit that to the TE of the stab to stiffen it up, but that's probaly overthinking things.

Stan Bidowski · « **Reply #11 on:** April 20, 2013, 01:06:41 PM »

Stay with the 6 x 3 MA if that's what you have. Just put it on backwards to slow the plane
down. The prop will then give you less speed. Cutting down the 6 x 3 to 5.5 etc. will likely
make the plane go even faster, not slower. Try it and see what happens. I would cut some
new lines at 45 feet and if that is too slow, cut a few feet off at a time till you find a good
length. You can also add a head gasket or 2, 3 etc. to slow the engine down a bit.
Some .049's can be much faster than another exact engine, so you will have to experiment a bit.
The APC's work well but break fairly easy. Make sure the prop is mounted so it rests at 3 and
9 o'clock when the prop is turned against compression. This is the resting place it will find
when the motor stops ( most of the time ). This will help stop props breaking on landing.

Curare · « **Reply #12 on:** April 20, 2013, 05:44:42 PM »

Stan, it's not landing that's breaking the props, well not intentional ones anyway.

The last two deckings have been caused by missing the exit to a square and a wingover. Like I say, you don't have time to think about hooking a corner, if you do you're in the dirt.

I'll have a play with longer lines, and smaller props. I think the 6x3 tends to overload the engine in hard spots, so a 5.5 on 43' lines might give me longer lap times, a little more thinking room, and a happy engine.

As they say around here, "suck it and see"

thanks!

Author Topic: Lap times, increase line length or drop some pitch? (Read 2206 times)

Curare

Lap times, increase line length or drop some pitch?

Jim Thomerson

Re: Lap times, increase line length or drop some pitch?

Reptoid

Re: Lap times, increase line length or drop some pitch?

Larry Renger

Re: Lap times, increase line length or drop some pitch?

Curare

Re: Lap times, increase line length or drop some pitch?

john e. holliday

Re: Lap times, increase line length or drop some pitch?

Paul Smith

Re: Lap times, increase line length or drop some pitch?

Curare

Re: Lap times, increase line length or drop some pitch?

ray copeland

Re: Lap times, increase line length or drop some pitch?

John Crocker

Re: Lap times, increase line length or drop some pitch?

Curare

Re: Lap times, increase line length or drop some pitch?

Stan Bidowski

Re: Lap times, increase line length or drop some pitch?

Curare

Re: Lap times, increase line length or drop some pitch?