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Old Jul 18, 2012, 07:20 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Sorry about the above.Can't seem to be able to edit more than about 10 lines
Stuart
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Old Jul 18, 2012, 07:21 AM
Herk
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Virginia USA
Joined Jun 2007
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Stuart - I flew with the new drag rudder setup this morning.

Was pleased to see it work well - no hint of adverse yaw - some proverse yaw noted at higher speeds. Dive tests were satisfactory - power on and power off. SM =2.5%

Was windy and turbulent so couldn't tell much more. Next flights will be with tip fins removed.
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Old Jul 18, 2012, 08:29 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Quote:
Originally Posted by HerkS View Post
Stuart - I flew with the new drag rudder setup this morning.

Was pleased to see it work well - no hint of adverse yaw - some proverse yaw noted at higher speeds. Dive tests were satisfactory - power on and power off. SM =2.5%

Was windy and turbulent so couldn't tell much more. Next flights will be with tip fins removed.
Herks,do you think your set up could make a tailless semi delta similar to the HoX flyable?There's a couple of guys over on the s/b edf forum who would find your work on this informative.
Regards Stuart
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Old Jul 18, 2012, 09:22 AM
Herk
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Virginia USA
Joined Jun 2007
1,637 Posts
The Horten X hang glider has huge elevons with the Frise hinging system.

I would think the plane would work ok as designed. Assuming that it's balanced as a Horten - i.e. SM ~ 18% or so.

It would require quite a change to the elevon system to incorporate drag rudders outboard. The span is so limited on that aircraft.

Long answer to say - not sure - probably not necessary.
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Old Jul 18, 2012, 10:31 AM
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Neat plane Herk :-)

Jens
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Old Jul 18, 2012, 11:13 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,204 Posts
Quote:
Originally Posted by HerkS View Post
The Horten X hang glider has huge elevons with the Frise hinging system.

I would think the plane would work ok as designed. Assuming that it's balanced as a Horten - i.e. SM ~ 18% or so.

It would require quite a change to the elevon system to incorporate drag rudders outboard. The span is so limited on that aircraft.

Long answer to say - not sure - probably not necessary.
Sorry Herks,I meant the HoX transonic jet they designed for the Volksjager programme.Thread on here somewhere,probably 1st page.
Regards Stuart
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Old Jul 18, 2012, 11:44 AM
Herk
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Virginia USA
Joined Jun 2007
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Mods completed after this morning's flight.

The plane now has a new look - much closer to the Northrop layout.

I'll probably start a new thread to pick up and follow on with the coupled drag rudder experience. Though, I think I'll make sure that it flys ok before I make that jump. Hopefully tomorrow morning will tell the tale.

If it looks really promising Stuart we can suggest that the edf guys take a look.
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Old Jul 19, 2012, 07:32 AM
I don't like your altitude
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I did a bit of sanding on the centre section last night,to try to get some sort of airfoil profile into it.The leading edge was no problem;not so the t/e.To get any sort of a taper on it I shall have to extend it quite a bit.
What the above proves is that the mechanism will have to be as thin as possible,which leads again to carbon fibre plate.
Next step after the proving(?)flights will be a working mock up of the centre section.
When I get the airframe complete I have an idea to make a gauge out of some 1.5m lengths of alu strip that I use for foam cutting,bolted together so I can set each of the wing positions to the centre line.Then mark each cog point and have a go at adding weight to balance.

Stuart
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Old Jul 19, 2012, 01:33 PM
Just call me crash for short
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United States, OH, The Plains
Joined Jan 2011
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Quote:
Originally Posted by Stupot46 View Post
I did a bit of sanding on the centre section last night,to try to get some sort of airfoil profile into it.The leading edge was no problem;not so the t/e.To get any sort of a taper on it I shall have to extend it quite a bit.
What the above proves is that the mechanism will have to be as thin as possible,which leads again to carbon fibre plate.
Next step after the proving(?)flights will be a working mock up of the centre section.
When I get the airframe complete I have an idea to make a gauge out of some 1.5m lengths of alu strip that I use for foam cutting,bolted together so I can set each of the wing positions to the centre line.Then mark each cog point and have a go at adding weight to balance.

Stuart
Stuart, here's an idea. How about cutting the form out of balsa and making a fiberglass or cf or kevlar, whatever, sandwich out of them. Take ~1/16 or 3/32 balsa sheet and cut your parts out, horizontal grain, and laminate them top and bottom with your composite cloth and epoxy resin. Lay the cloth 0/90 on the rack and on bias over the pinion cogs. With the amount of mileage these parts are likely to see, I'd recon the plane will have hit a tree / ground or some such before they wear out. The parts would be lighter, and easier to fabricate than trying to get them carved out of CF plate. I would think there would need to be some thickness with the parts or any amount of flex in the works would see the mating surfaces separating and causing all manner of trouble. Just a thought...

On another note, I see you renamed the thread. Now let us hope the pilot of this craft does not meet the same fate as the last one.

Mark
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Old Jul 19, 2012, 04:55 PM
I don't like your altitude
Stupot46's Avatar
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Mark,Jens et al,having come down to earth from the carbon clouds(what was I thinking)some I hope more rational thoughts.
Mark,the key point in your post above is, I believe,the need for rigidity and thinness.Jens mentioned size-maybe 1.5/2m?
Looking at what I've built so far,the key components are the wing root discs and the plate(s)that link them.These should still be carbon plate.I found this site- www.carbonmods.co.uk They sell 3mm carbon sheet at a price that's reasonable,and make hand cutting of it sound quite feasible.
My thoughts on the wing roots-to extend the disc into a solid U shape.This could be let into the wing like a ply wing joiner,but fixed.If the wing needed to be dismantled for transport this could be done at the pivots.
The bearing housings and hubs- ply or the balsa composite,easy enough to make accurately with a compass cutter.I'll have to re-check the plastic bearings,as Jens says the bigger the dia. the better.
The rack and it's teeth.To make mating easier and allow for any flex the teeth should be at least 6mm thick,and hard enough not to be worn by the disc teeth.Doubling up the carbon may be best,two strips let into a ply/composite slide.Tooth profile-the semi circular ones may work ok,I'll see how they feel on the mock up.
I apologise if some of my posts tend to ramble on a bit,but I find that getting something down 'down on paper' helps to refine my ideas,as well as gleaning invaluable info and advice from you guys.
Regards Stuart
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Old Jul 19, 2012, 09:01 PM
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Canada
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Erm.. It has both fins And a propeller.
Tough not to make that work IMO.
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Old Jul 19, 2012, 09:15 PM
internet gadfly
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Colorado
Joined Aug 2006
2,153 Posts
Gears have lobed teeth to prevent lash which is important in high speed power transmission applications and when the gear teeth themselves are part of the locking mechanism. If your locking pin were on the rack then strong, lash free, teeth would be impotent but with the pin on the gear wheel lash isn't an issue. When I was a kid I was in the habit of taking things apart. As I recall clocks have a lot of gears with triangular teeth. For slow turning they're adequate and much easier to make with the required accuracy than any kind of curved surface tooth design. Unless you're a machinist in real life you're not going to get all the teeth to mesh with curved surfaces. If you really think you need gears with curved tooth surfaces you can save yourself some time and aggravation by looking for things with cast plastic gears. You might find everything you need in a hand cranked egg beater

--Norm
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Old Jul 20, 2012, 12:01 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Quote:
Originally Posted by Bare View Post
Erm.. It has both fins And a propeller.
Tough not to make that work IMO.
Bare,I believe the 'Northrop is just a test bed in a staged development.
Stuart
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Old Jul 20, 2012, 12:43 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,204 Posts
Quote:
Originally Posted by nmasters View Post
Gears have lobed teeth to prevent lash which is important in high speed power transmission applications and when the gear teeth themselves are part of the locking mechanism. If your locking pin were on the rack then strong, lash free, teeth would be impotent but with the pin on the gear wheel lash isn't an issue. When I was a kid I was in the habit of taking things apart. As I recall clocks have a lot of gears with triangular teeth. For slow turning they're adequate and much easier to make with the required accuracy than any kind of curved surface tooth design. Unless you're a machinist in real life you're not going to get all the teeth to mesh with curved surfaces. If you really think you need gears with curved tooth surfaces you can save yourself some time and aggravation by looking for things with cast plastic gears. You might find everything you need in a hand cranked egg beater

--Norm
Norm,I have been down the 'off the shelf'route.The problem there is diameter,which needs to be as large as possible to give a long moment arm.I have found plastic rack strip online,though nothing as yet that looks strong enough.
You may well have a good point with the triangular tooth profile,I'll give that a try on the mock up.I've already made a tentative approach to a jobbing engineering firm who made prototypes for me at work,so that may be possible.
I was looking at the milling cutters and sanding drums to fit my Dremel clone;hand cutting the small number of teeth required wouldn't be too difficult.
More mental ramblings to follow.
Regards Stuart
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Old Jul 23, 2012, 09:17 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,204 Posts
I ran out of hinge tape for the second wingI've been using 3M Blenderm,which has apparently been discontinued.Quite a lot available online so I've ordered 5 rolls which should last me an age.
What are you guys using?
Regards Stuart
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