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Old Sep 01, 2012, 05:56 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Wow Kent,you're months ahead of me!My post above is the first time I've had any serious thoughts about a wing to instal the idea in.
The present crude effort is just to test the wing drive mechanism.If the cords are a success(I can see no reason why they shouldn't be)I probably won't bother with the geared arrangement.
I've made some "mental changes" to the design;a fixed nut and rotating screw,the servo mounted on the slide driving horizontal to the wing span.It should be possible to use the motion of the slide to change cog,which is another item on my to do list.Reversing the bands around a carrier pulley should achieve this.
So quite a bit of development needed.As to an air frame- how about a group design,incorporate some of Herks ideas?Builds either side of the pond.Love to hear any thoughts you and the guys have.
Regards Stuart
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Old Sep 01, 2012, 06:32 PM
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
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I must be missing some thing. I was under the impression that the attached photo IS the airframe/wing. I see control surfaces, horns and linkages.

Are you planning on a different wing configuration?

If so, Herk's prototype construction method of using flat plate foam is obviously a quick and durable way to go. For testing purposes, keeping the wing loading down to about 9oz/s.f. would ease the stress level of test flying.

Kent
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Old Sep 01, 2012, 11:43 PM
Just call me crash for short
Quick61's Avatar
United States, OH, The Plains
Joined Jan 2011
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Quote:
Originally Posted by Knoll53 View Post
I must be missing some thing. I was under the impression that the attached photo IS the airframe/wing. I see control surfaces, horns and linkages.

Are you planning on a different wing configuration?

If so, Herk's prototype construction method of using flat plate foam is obviously a quick and durable way to go. For testing purposes, keeping the wing loading down to about 9oz/s.f. would ease the stress level of test flying.

Kent
Hey Kent, I think that pic IS the prototype / test bed that Stuart was using. I think once he has all his ducks in a row he will build the real v1.0 of the ship. Maybe this is about the time we should be trying to talk him into a vacuum pump and epoxy resin /fiberglass / carbon fiber. I mean hokey smokes, he's gone this far - why not go all the way?

St-UUU-art....St-UUU-art....St-UUU-art (the presents chant for their champion with glee)

Mark
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Old Sep 02, 2012, 03:06 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,287 Posts
Kent,A bit of confusion!I should go to bed earlier.As Mark says,this is just a glorified chuck glider,it was your offer to test pilot that threw me
From the data on the 27.5 sweep in post#156 the area is just short of 2sqft.Weight including the balance weight is 7.5oz.
After the wettest summer on record the forecast for next week is quite good(ironically the schools reopen on Monday)so I'm hoping to test glide at some point.
Mark"don't expect to much and you won't get disappointed"somebody once said.I'm going to need a lot of help to convert this idea into a fully functional wing.
Regards Stuart
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Old Sep 02, 2012, 09:59 AM
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Knoll53's Avatar
United States, CA, Marina
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7.5 oz. OK, that is light.

Is that the ready-to-fly weight? If so, that is very light, about 4oz/s.f., which is a good thing. My current working theory is that small planes need to be very light, otherwise they fly so fast that it's hard for the pilot to keep up with it.

Although I live in the middle-of-nowhere as far a RC flying goes, I always try to find some help for the test fligths, even is it's just to launch the plane. Having a dedicated highly skilled test pilot would be ideal for test flying. For me the nearest flying club is 2 hours away.

In this video I asked a local newbie to help on the maiden voyage. Glad I did. I was able to get feed back from him that the plane did not feel like it would fly so when he launched I gave it full up elevator, which I would normally never do. As it turned out, the CG was way way too far forward and the plane would only fly with nearly full up elevator....it's better now.

ME 263 Komet - maiden voyage (1 min 39 sec)


Kent
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Old Sep 02, 2012, 10:06 AM
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Originally Posted by Quick61 View Post
Maybe this is about the time we should be trying to talk him into a vacuum pump and epoxy resin /fiberglass / carbon fiber. I mean hokey smokes, he's gone this far - why not go all the way?
I'm with you on that! Your disser treatment of the BLEED rudder was a good start. I may build the Skinny Wing next so maybe another example of balsa skinned foam wing will woo him over to the other side. Miniphase did a nice job in his 3m ship.

Kent
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Old Sep 02, 2012, 10:20 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Well,it's a bit agricultural buts it works.Slowly.Very slowly!
Check my math on this-
Servo speed@4.8v- 1.04 rpm
Thread pitch/mm- 0.7
mm/minute- 420
I'll order a 4or5 times larger drive pulley and belt,or what ever you guys think would give a fast enough response time in flight.Bob may be able to advise here?
Regards Stuart
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Old Sep 02, 2012, 10:30 AM
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Originally Posted by Stupot46 View Post
Well,it's a bit agricultural buts it works.Slowly.Very slowly!
My guess is that it will be too fast when you are flying. Things are going to happen quick when the CG starts moving around.

Here's a though problem for you. Is there a spot on the movable wing, that if a weight were place there, that it would provide the perfect overall CG in any sweep position?

Kent
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Old Sep 02, 2012, 10:47 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Kent,I couldn't believe that weight when I saw it on the digi scale.I reweighed on an old dial scale,same result!I know there's a lot of 2mm depron in there,but,as you say with all the hardware I expected to be a lot heavier.Building light has never been a fault of mine
As it's just a free flight exercise it'll get launched down a gentle slope and left to it's own devicesHopefully to stay in the air long enough to give some meaningful results.G/d has been recruited to video it,Wednesday after school is the plan.
Meanwhile back at the bench-while I'm waiting for the new drive I can get on with the discs etc.I'm going to go ahead with the extra carrier pulleys
Regards Stuart
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Old Sep 02, 2012, 11:02 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Quote:
Originally Posted by Knoll53 View Post
My guess is that it will be too fast when you are flying. Things are going to happen quick when the CG starts moving around.

Here's a though problem for you. Is there a spot on the movable wing, that if a weight were place there, that it would provide the perfect overall CG in any sweep position?

Kent
You may be on to something with the wing.If I get a chance I'll set the balance up again and try.There must be a point where the wing moves the same distance as the spacing in my original tests.
Regards Stuart.
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Old Sep 02, 2012, 11:42 AM
Just call me crash for short
Quick61's Avatar
United States, OH, The Plains
Joined Jan 2011
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Stuart, any help I can provide, you got it. You mentioned the Gulliver back in post #194 and mentioned foam wings with built up center. That particular design or not, the mix sounds like a very sane way to go with this build and the mechanics involved. Don't know if you have one or not, but a hot wire bow is a dead simple thing to make and when used with a gravity setup, (another dead simple thing to make) will produce some very impressive results. I actually like the gravity bow better than CNC for cutting wing cores. Now, cutting shapes for lost foam aluminum casting molds, that's a different story, but for wing sections, it's hard to beat the gravity cutter.

You also don't have to have a vacuum pump. Sure their nice and all, but you can always just put the cores back in the chucks and use something as simple as 5 gal. buckets full of wet dirt or sand to get a few hundred ponds,(couple hundred kg.) of weight and press them. Might have a bit thicker layer of epoxy, but the finish will be quite nice.

Whatever way you decide to go with the build, I'm sure it will represent well the effort you have put into this project, and as i said, whatever i can do from this end to help you along.

Mark

Mark
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Old Sep 02, 2012, 11:56 AM
Just call me crash for short
Quick61's Avatar
United States, OH, The Plains
Joined Jan 2011
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Quote:
Originally Posted by Stupot46 View Post
Well,it's a bit agricultural buts it works.Slowly.Very slowly!
Check my math on this-
Servo speed@4.8v- 1.04 rpm
Thread pitch/mm- 0.7
mm/minute- 420
I'll order a 4or5 times larger drive pulley and belt,or what ever you guys think would give a fast enough response time in flight.Bob may be able to advise here?
Regards Stuart
Servo speed is 1.04 RPM??? That does seem slow, and with the .7 pitch it would just creep along. Anyway, looks like you have plenty of room there for a larger primary pulley. Looks like from the pictures that you are at your limit for size on the drive pulley, any smaller, the belt binds and folds too much. Sense in this application you have no worries about torque load on the secondary, a much larger primary pulley can be used without having to worry about enough tooth contact on the secondary and the need for an idler pulley. A couple 3 teeth should be all you need. What's the tooth count on the secondary? Looks like about 12 or so from the photos but it's hard to tell.

Mark
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Old Sep 02, 2012, 12:01 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,287 Posts
Thanks Mark.I'm ok with foam cutting,especially on a constant chord wing like the G.I'm going to have to take the plunge and try some basic glassing-I think there's a fear of the unknown thing going on with it.
Fitting the gizmo in a centre section will need a nifty piece of design,as will the wing spars to the pivots.A few miles down the road yet though.
Regards Stuart
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Old Sep 02, 2012, 12:13 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Quote:
Originally Posted by Quick61 View Post
Servo speed is 1.04 RPM??? That does seem slow, and with the .7 pitch it would just creep along. Anyway, looks like you have plenty of room there for a larger primary pulley. Looks like from the pictures that you are at your limit for size on the drive pulley, any smaller, the belt binds and folds too much. Sense in this application you have no worries about torque load on the secondary, a much larger primary pulley can be used without having to worry about enough tooth contact on the secondary and the need for an idler pulley. A couple 3 teeth should be all you need. What's the tooth count on the secondary? Looks like about 12 or so from the photos but it's hard to tell.

Mark
Missed this one.Think that's a 12t,it's 10mm dia.I'll check later when I go on the site.The prices are reasonable so I'm going to order a 2x and 3x primaries with belts to suit.
Stuart
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Old Sep 02, 2012, 12:25 PM
Just call me crash for short
Quick61's Avatar
United States, OH, The Plains
Joined Jan 2011
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Quote:
Originally Posted by Stupot46 View Post
[snip]

Fitting the gizmo in a centre section will need a nifty piece of design,as will the wing spars to the pivots.A few miles down the road yet though.
Regards Stuart
As far as "Fitting the gizmo in a centre section" goes, I've already conjured up a few ideas in the last few moments depending on how much real estate there is in the design of the center section. I'll fire up the CAD in a bit and drop a few ideas on ya to mull over while traveling those few miles.

Mark
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