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Feb 16, 2017, 01:54 PM
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Knoll53's Avatar
Quote:
Originally Posted by EdSoars
Photos hopefully show the control throws for the Dreadful Maiden.
Is Dreadful Maiden the model name???

Is sounds somewhat softer than the ever popular Dreadful Wench.
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Feb 16, 2017, 03:07 PM
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EdSoars's Avatar
Dreadful Maiden could be an appropriate name, and Tiger Moth was really for a 54" span, straight leading edge planform, so maybe something more imaginative than Tiger Moth 60 would be good. But then we'd have to change the title of the thread.

I'll spend time on a new name if it survives the first flights and flies well. The 2m version with straight trailing edge and outboard elevons will definitely deserve a new name.

I'm surprised that the Dymond 150 servos on the ailerons have a good amount of free play. They actually rattle when the wing is shaken. I'm hoping this won't cause a disaster on the TM60 seeing that they don't serve as elevator. Pretty disappointing.

Does anyone have a recommendation for a metal gear servo 12mm thick or less, digital or analog, that has very little free play and good centering? I'm going to need some for the 2m stretch. The KST and FrSky servos are good but not consistently good.
ed
Feb 16, 2017, 04:10 PM
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The KST DS125MG are not consistently good? Thanks for the tip. I have bought and used only 6 of them and they are by far my favorite servos. I do dislike the thin gauge lead wires.
Feb 16, 2017, 06:01 PM
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EdSoars's Avatar
I have bought 4 KST 125's and 1 was sloppy. Maybe that's unusual and the next 10 will be great. I like the 4 FrSky D25MA's I've bought because of their wing mount tab orientation. They seem more adapted to fine control rather than fast response. But again 1 had some gear lash. Overall, they are good value.

Just wondered if there was something better for under $25.00. Or the same for less than $20.

Has anyone tried the Power HD wing servo? Metal gears, digital, and a coreless motor for $10.00! It may be worth trying a few.
Feb 18, 2017, 09:23 PM
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Knoll53's Avatar

Thoughts on first flight


Quote:
Originally Posted by EdSoars
Do all these control travels look decent to you guys? This is all at high rates. Low rates are 70% for aileron, 60% for elevator.
They look good to me, but it depends on the conditions in which you'll be flying.

I have to admit, I thought that you were worrying too much with this question......THEN I went flying today in 30mph winds and suddenly my well behaved little sloper was a real handful. Control throws were just A LITTLE too much and I was hanging on for dear life. Almost hit the cliff on the left....corrected.....then almost hit the cliff on the right. Finally hit ME, broke the 72mhz antenna and I called it a day.

Also, I was flying with new dark tinted ski goggles that did not allow me to wear glasses. . I could hardly see a thing. These goggles are needed for the blowing sand I had to watch the video back home to see what happened... These things add up so if too many things start going wrong, don't fly.

I recommend some expo to give yourself a small advantage. I think that expo would have helped me quite a bit today.
Feb 18, 2017, 10:15 PM
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EdSoars's Avatar
Thanks Kent. This is my first 3-servo plank and I had no idea what the elevator travel should be.

Your experience sounds familiar. I start with fairly high rates with generous exponential, and low rates with less expo. The insurance is one of the sliders which has elevator trim, LOTS of elevator trim. Once a decent range is found for high and low rates, I reduce the trim volume to give me thermal float on full up and inverted cruising on full down.

If I don't keep things simple, with no toggle switches for different settings, my planes last longer. And I NEVER put elevator trim on the throttle stick. It gets bumped too easily and suddenly having a lot of down trim to deal with and no idea what happened, is NOT GOOD.

ed
Feb 22, 2017, 05:52 PM
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EdSoars's Avatar
So, I dashed out of the house without the video camera. FB Mike tossed the T-Moth into the wind, and the maiden flight lasted about one-half second. WHUMP. Stepped down the hill, retrieved the Moth, added 1/18 inch up trim to central elevator.

Toss again. Fly for 30 minutes.

Conclusions: central elevator works very nicely, but needs less travel: it's HOT in a dive. Outboard ailerons need some differential for axial roll.

All in all, a delightful performer. Stripped elevator servo gears during an on-the-rocks landing, will replace with some kind of metal gear servo. I will also program butterfly on the throttle stick.

And I WILL get video!

Ed
Feb 22, 2017, 08:42 PM
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That's good news. So did you toy with the cg at all? Sounds like just the one flight. I would guess that some up elevator deflection would be needed for trimmed slow flight. I have to launch my planks hard at an upward angle to have any luck at missing the earth.

If you are able to make a video, I have a request. Let's see one of those rock landings that you have been describing. They sound challenging.

Mar 08, 2017, 02:29 PM
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Peter: sorry for the delay answering your question about what airfoil I use. Oddly enough, it's a PW 51! I haven't found a better one for Re range, ease of trimming, aerobatic flight and ease of building. God knows I've tried!

Kent: here are a few shots of what we laughingly refer to as our "landing zone". The situation puts severe limits on my designs. The planes must be able to survive out-of-sight landings, and the short trees create lots of low-level turbulence. Because there is frequent damage, they must be easy to build and repair, and can not cost too much.

Tailless in general is a good solution, and planks may be the best, once I solve the glide path control to some extent. I'm reluctant to use more than three servos, and will be playing with some creative mixing. That is, as soon as we get some decent weather.

Ed
Mar 09, 2017, 01:49 PM
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Next stage in moving into high aspect ratios: Stretch the Tiger Moth to 2 meters.

Structure is nothing unusual: Expanded polyethylene fuselage in a FG sock with a CF tail-spine. EPS wing cores are sheeted in 1/64 plywood, This one may get a powered fuselage if flights go well. It still needs control installation so it will be a little while yet. Like the Tiger Moth, it will have central elevator and outboard ailerons with multiple mixes to try out.

ed
Mar 10, 2017, 03:13 AM
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So Kent: here are snapshots of 4 out of 6 so-called "landings" yesterday. Video was impossible due to the wind coming straight out of the sun. It was also very turbulent.

Notice that the "landings" have more to do with trees than land. If I want to be able to fly, as opposed to build and repair, my aircraft need to be able to survive some pretty nasty impacts. The second Moth landing broke the elevator servo gears. Hitec HS 56 karbonite gears. Back to all metal gears for me, hang the expense.

The TigerMoth has a wing loading of 9 oz/sq ft. The wind was 15-25 mph, and the 'Moth penetrated very easily. The handling is very predictable and nimble. The CG is at about 3% of MAC. The central elevator is effective for my flying, and in crow, it overpowers the ailerons, so that I had to reduce the throw. It still needs to be reduced. Also, the rolls are not yet axial.

I'll get video some day when I can, probably later in the summer when the sun is higher.

BTW, the second two landings are a Slope Monkey: a handful in the turbulence, but 'way fun!
Mar 10, 2017, 04:50 AM
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Stuart A's Avatar
Wow! Rocks and a hard place
Maybe you should land in the trees and employ a slope monkey to retrieve stuff
Mar 10, 2017, 09:34 AM
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Isn't it amazing how wildlife (RC gliders) adapts to it's surroundings.

I guess that there will be no 8lb all glass ships for you. EPP all the way.
Mar 10, 2017, 07:59 PM
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Stuart, a friend of mine suggested using bacon grease on the fuselage, and my dog, who loves chasing the planes, would ALWAYS be able to find them. Now, with digital servos, he hears them and goes to them. Retrievals might produce punctures, however!

Kent: not quite all epp. The Tiger Moth has epp in front of the spar and eps behind. Hard LE's and FG or 1/64 ply skins are very tough. I like 1/2" spruce LE's. Finding the right balance between resilience and rigidity at each place on an airframe is the name of the game.

Conventional planforms with deep-chord flaperons work well too, as they can slow way down. The tailbooms get repaired pretty frequently though. Swept wings survive well too, as the sweep converts some impact energy to rotation. But the best seem to be planks, even though it's tough to slow them down. Mine run 9-12 oz / sq ft, and 2 meters is the limit for wingspan. I mount the wings with nylon bolts, one big one at 25% chord, and one small one in front of the TE that can break easily, letting the wing rotate relative to the fuselage.

The nicer, bigger planes are only flown on good days when we can walk down to the open areas while still flying the planes. Tricky at times. Sometimes when there are no clouds, we can stay on top and land below, following the plane's shadow to touchdown.

It's a whole-body exercise, this slope soaring! Tactical thinking is useful too!
Last edited by EdSoars; Mar 10, 2017 at 08:07 PM.
Mar 14, 2017, 09:13 AM
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I'd take your rocky slope over my "there are no slopes around here, son."

Looks like a beautiful landscape.

-Dave


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