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Venus 40 Problem

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Old 06-10-2003, 11:09 PM
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Bad Tooth
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Default Venus 40 Problem

Ok guys, I have a gp venus 40 that does a pretty strange thing. It flies great except for one problem, when I hit about 50% deflection on the elevator (mostly when looping) it starts to spin to one side. during the first flight, it always seemed to spin to the left. I got it home and found that it was a little heavy on the left side, so I added weight to the right wing and went out again. But today it does the same thing!? I didn't really pay attention because I was so upset, but I think it was doing it to both sides and still with a tendency to the left?
This is a difficult problem I know, and unless you have seen it fly it's tough to understand, but if any of you have seen this before, or it sounds familiar. . . Could it still be a lateral balance problem? could a nose to tail balance problem cause this? (it is about a 1/4" nose heavy).
Thanks in advance to all of your replies.
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Old 06-11-2003, 12:37 AM
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Default Venus 40 Problem

Being nose heavy will help counteract that. What you have is most likely a high speed stall with one wing stalling first causeing it to drop befor the other, hence the roll out.
Do you have the controls set higher than recommended? To much elevator is likely the cause.
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Old 06-11-2003, 02:20 AM
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Default Venus 40 Problem

My control throws are set at the recommended deflections. This happens before I reach the full deflection on the elevator? Is there anything else that it could be? If being nose heavy couteracts the high speed stall should I move the c.g. forward?
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Old 06-11-2003, 02:53 AM
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David Cutler
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Default Venus 40 Problem

It's definitely a snap, almost certainly caused by too much elevator movement.

Actually, very tight loops are possible with a lot less elevator than you'd imagine. I would suggest you have 2 rates on all control surfaces. One for normal aerobatics and switch to high rates if you want to go mad and snaps are what you are looking for.

-David C.
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Old 06-11-2003, 01:41 PM
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Default Venus 40 Problem

In reference to what David C says:

I had a similar problem. I'm the type of flyer who likes to throw them sticks all over the place (mainly from trying to get a trainer to do aerobatic/3D stuff). I moved from the trainer to a 3D plane. I had the same situation (loops snapping out). What I thought was a problem with the plane turned out to be my flying. I had to learn to take it easy on those sticks, ease into the loop, and no more slamming on them sticks.

If you think this is your problem, try this:
A very good flyer at my field (probably the best in the region) told me to practice flying helicopters on the simulator (that will soften my controls up, smooth them out), and it did work...Now I can make my loops as tight as I want without snapping out.

and/or:
If you have a simulator to play with, just pick a 3D plane (extra, cap, edge, sukhoi (my favorite))and practice tight loops until you get the hang of it.

Good Luck!!!
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Old 06-11-2003, 01:57 PM
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Default Venus 40 Problem

If you have washin in one or both wings it will snap out of a loop too. Make sure the wings are flat or have a bit of washout.
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Old 06-11-2003, 03:14 PM
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Default Venus 40 Problem

so you're saying that I can still pull tight loops, but I have to ease into the full position on the elevator?
and flypaper, what is 'washin?' and if I have it how do I correct it?
I guess that I got used to slamming my sticks on the trainer too. but what is scary is when I need to come up out of a loop quickly I really can't because it snaps. But I could with my trainer. is this a characteristic of this plane? do I just have to get used to it or can I change something on the plane?
Thanks guys!
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Old 06-11-2003, 05:35 PM
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Default Venus 40 Problem

Strupp 22:
The tip of the wing at the trailing edge should be tilted up a bit compared to the root. Thats washout. Causes the root of the wing to stall before the tip. If the tip is tilted down a bit at the trailing edge,thats wash in. If so, use a heatgun and see if you can twist the wing to put about 1/4 in. of washout in it. Make sure both wings have the same amount.
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Old 06-11-2003, 05:48 PM
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David Cutler
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Default Venus 40 Problem

Originally posted by Flypaper
Strupp 22:
The tip of the wing at the trailing edge should be tilted up a bit compared to the root. Thats washout. Causes the root of the wing to stall before the tip. If the tip is tilted down a bit at the trailing edge,thats wash in. If so, use a heatgun and see if you can twist the wing to put about 1/4 in. of washout in it. Make sure both wings have the same amount.
Yes true.

But in this case any snap has almost certainly been caused by too much elevator movement.

I doubt if he needs to alter the wing shape just because of that. Apart from anything, it will make other characteristics change.

No, the Venus wing is perfectly OK as it is. There is no way he will want to do such a drastic thing as heating and bending the wing.

I much prefer the suggestion that he practices with, maybe, a simulator.

-David C.
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Old 06-11-2003, 08:39 PM
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Default Venus 40 Problem

Originally posted by David Cutler
It's definitely a snap, almost certainly caused by too much elevator movement.

Actually, very tight loops are possible with a lot less elevator than you'd imagine. I would suggest you have 2 rates on all control surfaces. One for normal aerobatics and switch to high rates if you want to go mad and snaps are what you are looking for.

-David C.
Dave, I have dual rates on elevator and aileron. I can do nice smooth LARGE loops on low rates but how do I do a tight loop with this plane? And if I ever get into trouble where I need a lot of up elevator immediately how do I get it without snapping?
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Old 06-11-2003, 08:53 PM
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Default Venus 40 Problem

so you're saying that I can still pull tight loops, but I have to ease into the full position on the elevator?
Hold on....slow down a moment. I am referring to what David C said. Yes, its possible to pull tight loops, how tight depends on the plane and your skill (and I bet one problem you are having is using too much elevator). Easing into the elevator will allow you to see how much you can give before it snaps out. One thing I did was climb high and pull multiple loops, giving more elevator on each loop until the plane snaps out. That way I knew exactly how much it took (of course theres throttle control too). Now bear in mind that the Venus is a pattern ship, its not designed for tight loops, rather bigger, smoother ones so don't expect any miracles...

You will find that loops rarely require full elevator position (other than a trainer). In fact, about the only time I use full position on any surface is when I'm doing some radical 3D stuff (hovering, snaps, spins, walls, elevators, blenders, etc.).
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Old 06-11-2003, 08:58 PM
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Default Venus 40 Problem

Thanks guys, I'll see what I can come up with the next time I go out.
Trevor
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Old 06-11-2003, 11:08 PM
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Default Venus 40 Problem

Going by the fact that Strupp says he was using the recomended settings. Just make sure the wing is straight.
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Old 06-11-2003, 11:35 PM
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Default Yep

All the above are good responses.

I have a Venus, built stock, with an OS .46FX, and it will do very tight loops. Here are a couple of tips to help stop your snap problem.

1. Be sure and take the time to balance the model and set the control throws as in the instructions, before experimenting with any changes.... Always a good way to start.

2. The way to fly "safe" is to set your highest rate so that it's just below the threshold of the snap, at the speed you usually loop at. An easy way to check this is to watch your loops as you fly them. If the loop is smooth, great. If it's "jerky", more like an octagon than a loop, that tells you that you're right on the edge of a stall/snap.

3. Aerobatic planes are made to snap easily, for crisp entry into maneuvers that require it, such as a spin. Trainers are usually built so that the wing will (more softly) stall and recover before the stall can intensify.

Once you get the Venus trimmed, it's a lot of fun to fly, especially in knife edge. Here's an example trim chart that may help. http://www.nsrca.org/trimA.htm
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Old 06-12-2003, 01:39 AM
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Default Venus 40 Problem

Now bear in mind that the Venus is a pattern ship, its not designed for tight loops, rather bigger, smoother ones
Exactly!! Try to envision youself in the plane while it's flying. If you think you'd be uncomfortable during the maneuver, then you're overtaxing it. If you're unhappy with the tightness of loops and other maneuvers, then maybe you need a FunFly or 3D plane.

Pattern ships and the majority of sport (& scale) planes just aren't meant to have the sticks "thrown" wildy. If it's aerobatic this type of flying WILL produce snaps, out of loops and at times, even in a tight turn.

Personally, I don't like watching RC flying where maneuvers would kill the pilot.
Dennis-
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Old 06-12-2003, 02:57 AM
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Default Venus 40 Problem

Yep, the Venus isn't a 3D machine, but if you want it to snap (especially a climbing one) it does a beautiful fast one even with low rates!

-DC
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Old 06-30-2003, 09:28 PM
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Default Venus 40 Problem

Well guys, thanks for all of your input on my venus problem. I planted it right in the dirt today!! I was just getting used to it and learning how much was too much on the elevator, I was really having a lot of fun, but that darn snap-roll finally got the best of me. I made a fast fly-by over the runway and then pulled up, flipped inverted while climbing and then eased back on the elevator, planning to just loop toward the runway, and then do another fly-by. well, the ground kept coming faster and faster, so I kept easing back on the stick - when I finally hit that point where it snapped out. It happened when I was about 10 ft off the deck, nothing I could do at that point, it spiraled right into the dirt! It was quite a sight. I guess I needed a little more altitude to pull that off! It was fun while it lasted though.
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