stunthanger.com
Design => Stunt design => Topic started by: Tim Wescott on November 18, 2010, 12:11:34 PM
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I'm an absolute beginner at this stunt stuff, although I have years of building and sport flying behind me.
Between family commitments and geography I can't make it to paved flying circles for anything but contests. The field that I have to fly from is grass, and not terribly smooth at that. My current plane is a taildragger, and trying a smooth takeoff is a real roll of the dice -- sometimes it works, sometimes I nose over and break a prop. If I want to takeoff reliably I need to hold up elevator and pop off the ground quickly. This is giving me some really bad reflexes when I fly off of a decent surface!
I'm thinking that the next plane I build should have trike gear -- I'm thinking that with a wheel right out in front I should have a much better chance at doing a 'real' takeoff on the field that I have, which means that I'll be able to practice all of the beginner pattern.
So my question is: Do you fly with trike gear, or have you? Does trike gear seem to be a reasonable approach to take to solve my problem? (an alternative is to fix the circle, which I can only do to a limited extent -- I can fill in the worst of the dips, but it'll always just be mowed weeds).
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Go to Delta Park. The weird wind there will make you crash, but you can take off.
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Go to Delta Park. The weird wind there will make you crash, but you can take off.
I'd love to, but the trip to and from would take up more than half of my available "driveway to driveway" flying time, and my understanding is that you have to compete with the soccer moms for space to fly on Saturdays.
Heck, if I lick the 'off grass' problem well enough to take off amongst hoof prints and horse turds, I'll be practicing during the week just a step away from my house.
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Can you put down a runway? If you can kill a spot of grass, a length of rolled roofing will work well, otherwise maybe some carpet runners that you can pick up after flying.
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Can you put down a runway? If you can kill a spot of grass, a length of rolled roofing will work well, otherwise maybe some carpet runners that you can pick up after flying.
That's a thought. Anything permanent would have to be run by the club, but that may wore.
I think the most expedient thing now, if it works, is trike gear. But eventually -- and especially if we get more CL flying in this club -- the circle could get improved.
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Nils Norling and his gang of Lawn Darters over in Redmond used to put down a sheet of cheapo panelling to take off of and keep fuel spills off the lawn. Check around Lowe's or Home Depot's dumpsters... LL~ Steve
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I have used the window blinds ( like the bamboo ones,) small round sticks made into a blind, roll it out,, take off, then roll them back up again and stuff them into the car,, The ones I found were about 4 feet across, roll out to 6 feet long. The "sticks" are plastic and about 1/8 in diameter
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I have to admit that when we were kids (well, teenagers), we went to the local school and spread herbicide on a small area of the athletic field off to the side. The grass would die in that area and we used it as a take off pad. I'm sure the groundskeeper probably wondered why the grass died in that area.
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I fly trike geared planes a lot. If the grass is really thick, I will apply some up on take off roll, to slightly lift the nose wheel. As the plane acceleraates, I'll ease off the up, just leaving enough to lift off smoothly.
The nose wheel will help avoid nosing over, and breaking props. I've never had any type of nosing over problems, but until I learned to finese the take off roll in thick, or heavy grass, I sometimes couldn't get enough speed built up to take off.
Trike gears on planes designed for them are easier to ground handle in almost any conditions. H^^
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I'm an absolute beginner at this stunt stuff, although I have years of building and sport flying behind me.
Between family commitments and geography I can't make it to paved flying circles for anything but contests. The field that I have to fly from is grass, and not terribly smooth at that. My current plane is a taildragger, and trying a smooth takeoff is a real roll of the dice -- sometimes it works, sometimes I nose over and break a prop. If I want to takeoff reliably I need to hold up elevator and pop off the ground quickly. This is giving me some really bad reflexes when I fly off of a decent surface!
I'm thinking that the next plane I build should have trike gear -- I'm thinking that with a wheel right out in front I should have a much better chance at doing a 'real' takeoff on the field that I have, which means that I'll be able to practice all of the beginner pattern.
So my question is: Do you fly with trike gear, or have you? Does trike gear seem to be a reasonable approach to take to solve my problem? (an alternative is to fix the circle, which I can only do to a limited extent -- I can fill in the worst of the dips, but it'll always just be mowed weeds).
Hi Tim,
Does your problem model have wheel pants? Because these can be caught on the grass and flip the model onto its nose real quick.
Or you could look at bringing the wheel axles forward (easily done if you can change the undercarriage legs or make a bracket up to move a stub axle forward) and then use either wider or larger wheels.
But my vote would have to lie with the use of a temporary take off surface and I have seen thick black rubber sheet used.
Good luck, and we had some idiots enter the flying field where I go to and drive around in circles chewing up the dirt - that came pretty close to wrecking the surface for the club!
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My experience flying off of grass is to use larger wheels. Also bend the gear legs further forward. On the Brodak Olympic I had two sets of gear. One for grass with no wheel pants and larger wheels. The other set per the plans. H^^
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Got a buddy to hand launch?
W.
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I'm an absolute beginner at this stunt stuff, although I have years of building and sport flying behind me.
Between family commitments and geography I can't make it to paved flying circles for anything but contests. The field that I have to fly from is grass, and not terribly smooth at that. My current plane is a taildragger, and trying a smooth takeoff is a real roll of the dice -- sometimes it works, sometimes I nose over and break a prop. If I want to takeoff reliably I need to hold up elevator and pop off the ground quickly. This is giving me some really bad reflexes when I fly off of a decent surface!
I'm thinking that the next plane I build should have trike gear -- I'm thinking that with a wheel right out in front I should have a much better chance at doing a 'real' takeoff on the field that I have, which means that I'll be able to practice all of the beginner pattern.
So my question is: Do you fly with trike gear, or have you? Does trike gear seem to be a reasonable approach to take to solve my problem? (an alternative is to fix the circle, which I can only do to a limited extent -- I can fill in the worst of the dips, but it'll always just be mowed weeds).
When I was an avid CL Stunt flier, I loved trike gears. You have a lot of options in getting a smooth landing and take-offs are a piece of cake.
In long grass, let it start rolling, keep the pressure off the nose gear and adjust until you are ready to go airborne, then ease it off. One problem that many CL fliers and early RC 3-gear fliers made was to set the main gear too far aft of the C.G. Then it takes too much back-pressure (up control ) to get the nose to lift. When it does it REALLY DOES and the model may well jump into the sky before it is really ready to fly. %^@ This also happens when the nose gear is set too low and the wing angle-of-attack (AOA) is in the minus figures. Once it has adequate speed to break the negative lift, it will just jump into the air and there goes a bunch of "smooooth" points.
With the model sitting at a positive angle-of-attack, especially more than than a degree or so, it may well
want to fly early although there is yet enough airspeed to really do so. In a flapped, symmetrical airfoil, the true AOA changes as some up-elevator is applied as the flaps go down, and therefore the wing is really no longer aerodynamically symmetrical. Watch so many RCers try to fly with a tail heavy tri-gear or conventional, model jumps into the air, rolls left, they apply right aileron to correct, so the down left aileron adds drag to the left wing and decreases the airspeed, thus reducing lift while the right up-aileron yaws forward but the added airspeed adds more lift thus the model rolls -- usually a snap roll -- and end of the flight does happen. Many a RCer sees just a few yards of flight, especially when the CG is aft of 28% MAC, especially with War Birds. Now most CL fliers have the advantage of outside yaw due to the rudder and line-rake. Very few RCers ever think of rudder when the machine breaks ground!
I always start with a CG at 23-25% and work back from there. Then I seem to always have smooth take-offs, except for those Old Timers with a conventional gear ahead of the wing. :o In RC I TRY to think rudder until the model is well airborne.