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goatherder

Another n00b question

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Does anybody KNOW how stretching a Long-EZ fuselage an extra few inches - and yes, I mean a stretch between the wing and canard - would affect the flight characteristics of the aircraft?

 

Assuming that you could move weight around to re-balance fore & aft, what difference would say...a 6" stretch make in the way the thing flies?

 

(And yes, I've read the other threads with all the warnings and "thou shalt nots"...but I didn't actually see the question answered)

 

I know there's some real smart fellers on this forum...can anybody answer this?

 

Also, I have it on good authority that if you move the landing gear 2" aft the plane will stand on its gear rather than falling on its ass as soon as you step out of it. How about that?


Marc Oppelt

Olympia, WA

http://picasaweb.google.com/oh.u8it2

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I have it on good authority that if you move the landing gear 2" aft the plane will stand on its gear rather than falling on its ass as soon as you step out of it. How about that?

 

G'day

 

A wise american president used to say "Trust but Verify". I see the words, but it is hard to verify who the "good authority" is.

 

If you post such a statement you should be willing to post the authority. I am sure they would not mind if they are a true authority.

 

In Rutan I trust.....(and the 1000 plus types currently flying over the last 30 years....)

 

Jeff

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I do know one thing. Here it is If you move your gear back you will increase your rotation spead. Which in my small mind lengthens take off roll. The tipping thing is a hastle but I want to rotate if you know what I mean. STeve build on


Steve Harmon

Lovin Life in Idaho

Cozy IV Plans #1466 N232CZ

http://websites.expercraft.com/bigsteve/

Working on Chapter 19,21

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I have never built an aircraft or even sat in a LongEZ... (fellow n00b disclaimer).

 

Does anybody KNOW how stretching a Long-EZ fuselage an extra few inches - and yes, I mean a stretch between the wing and canard - would affect the flight characteristics of the aircraft?

I briefly thought about this also (then after guidance from the more experienced posters, did more research & ran screaming from the idea). http://canardzone.com/forum/showthread.php?t=4493

 

Canard designs are very sensitive to cg and aerodynamic center changes (more so than conventional aircraft). If the changes to static balance don't scare you, try looking at the dynamic effects.

 

The current design has known characteristics on a good range of weight/CG. You need to evaluate whether it's worth a few inches to risk (at least) sacrificing some of that range. Extra baggage room / legroom may not do much if you can't carry both fuel and passengers... or need to shift ballast around ... or effect the handling qualities of the aircraft.

 

That's real aero-engineering stuff and for me involved more effort/risk than was remotely worth it. I suggest that if you have to ask this question, you need more research before you make the decision.

 

 

Also, I have it on good authority that if you move the landing gear 2" aft the plane will stand on its gear rather than falling on its ass as soon as you step out of it. How about that?

1) By shifting the cg forward you put more load on the nose gear. Questions you need to ask are: Can it structurally handle it? Do you have enough canard lift to rotate the nose on takeoff? Answer the previous 2 questions for the entire range of weight/CG.

 

2) How will you change the structure to support the main landing gear? How will this affect the CG?

 

I disliked the "grazing" aspect of this aircraft when I first looked at it, but like most things on the aircraft, I've since come to appreciate the simplicity.


I don't care, I'm still free.

You can't take the sky from me.

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Well I was digging around and found an email address for a guy who built a modified plane that led to the developement of another plane that everybody holds in high esteem. He was kind enough to email me back to answer my dumb questions even though he didn't know me from Adam, but I don't know that he'd want to be involved in this discussion. 'Nuff said.

 

Apparently moving the wheels aft 2" increased his rotation speed about 5kts. Apparently they stretched the fuselage 11" and put full controls in the rear seat.

 

That would be cool. My wife could land the plane if I have too many in-flight cocktails...

 

And OBVIOUSLY I'd need to do more research before I made a decision. Duh.

And maybe ask some questions too.


Marc Oppelt

Olympia, WA

http://picasaweb.google.com/oh.u8it2

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Some more non-building noobie comments...

 

It's something I've wondered, and like the previous poster I figured that there are things I clearly don't understand well enough that I would modify them unless it was well established that it was safe to do so.

 

Having said that, I believe the Berkut has a lengthened fuselage, not to mention a bigger engine to counterbalance it.

 

Also, I probably weigh 30kg less than some builders. I see a lot about people building longer noses in order to move the battery forwards... Perhaps I could afford to build a slightly longer fuselage with more room for the passenger, even if many other people couldn't?

 

(I'm seconding the question).

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Sounds like you boys want a Berkut.

Watch Barnstormers and E-Bay and you'll eventually find one.


T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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Recently, i got in touch with a Long builder here in the uk. This Gent has kindly offered to let me look at his Bird at some point in the near future. It'll be great to see one in the flesh and hopefully see if i can fit in one ( not that i'm a fat person, just dodgy knees:o ) If there is enough room then stock dimensions mine will be:)

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I DOES want one. Just can't afford all that Farbon Ciber.

 

Maybe a little for the wing spars though.

Okay .... that's $1400 (roughly). It will take 10 50' rolls of West 703 and that would be if you were cutting your cores with the Berkut templates.

If your spar caps are deeper ........ plan accordingly.


T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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I lengthened my Limo EZ by 4.5" and added an extended nose. The canard went further forward and was increased to 147". This was done per the original Limo EZ that Sam Kriedel designed and later evolved into the Berkut. All mods were done to preserve the rotation qualities, CG and MAC of the original LongEZ.

 

Joe Berki

Limo EZ

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Ok, well it was his son I was communicating with. He said he thought it was an 11 inch stretch; but his memory was a bit fuzzy as the plane was completed 20 years ago. Maybe he meant 11" LOA.

 

He also mentioned making the canard longer but said they ended up cutting it back down.

 

What about fuselage widening?

 

Seems like you could widen the entire fuselage/spar combo by a 2-4" and still use the plans strakes and stuff. Of course cowlings would be roll-your-own.

 

Do you have drawings by chance?


Marc Oppelt

Olympia, WA

http://picasaweb.google.com/oh.u8it2

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It was probably 11" when you add the nose and the 4.5 between the front and back seats. I increased the width at the pilot shoulders to 24" but curved the fuselage giving me 26 to 28" at the hips. Firewall went to 22". I went deeper also about 4" more and sit more upright. The Kreidels were going to trim the canard but they never did. I corresponded with Sam when I built the canard.

 

Joe Berki

Limo EZ

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Now this is what I was after when I started this thread and I asked the question "does anybody KNOW...?"

 

I knew somebody out there did. You do. Thanks for the reply.

 

If you don't mind, I'll get in touch with you when I start building bulkheads and such....and maybe pick your brain a little more.

 

Thanks again Joe.


Marc Oppelt

Olympia, WA

http://picasaweb.google.com/oh.u8it2

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Goatherder,

 

Attached is a pic that shows the results of curving the fuselage from the inside. You can see more at the thread Progree Limo EZ

 

Joe

post-1197-141090166288_thumb.jpg

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Nice looking plane man...definitely an aesthetic improvement. Looks like you used thicker foam for the side panels and then hollowed out the inside ???

 

Actually, it just occurred to me that one could hotwire out the hollow, and then glue the offcut to the opposite side to form a curved panel. Just a thought...

 

RE: Main gear position -

 

I do know one thing. Here it is If you move your gear back you will increase your rotation spead. Which in my small mind lengthens take off roll. The tipping thing is a hastle but I want to rotate if you know what I mean.

True - but doesn't takeoff roll depend on how fast you accelerate to rotation speed?

 

Nothing I own is slow. I'm thinking an EJ25 Subaru w/ an Ivoprop. Maybe hang a vortec blower on the front after I get things sorted out.

 

Stand on the brakes, set the prop to fine pitch, mash the gas, wait till she starts to skid and then drop the brakes. Kinda like power-brakin' my old Firebird.


Marc Oppelt

Olympia, WA

http://picasaweb.google.com/oh.u8it2

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When you move your gear back you put more weight on the nose wheel. This is why it does not tip over. It also makes your canard lift more weight thus to get that extra lift you have to go faster. The bigger the motor you have the more thrust you can develope thus speed increases.

 

Bigger motors weigh more so what I am getting at is everything on these planes is a compromise to make them work the way Burt thought they should.

 

Go ahead and put a car motor in your plane and spend your time tinkering instead of flying. I like to fly I tinker enough at work. STeve build on


Steve Harmon

Lovin Life in Idaho

Cozy IV Plans #1466 N232CZ

http://websites.expercraft.com/bigsteve/

Working on Chapter 19,21

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No, I used the same 3/8" foam that is used in the Cozy. I just placed it into a jig while the inside layup was done. Eracer plans start with a 3" thick piece of foam and carve it to shape. Seemed like a lot of waste.

 

Joe

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Actually, it just occurred to me that one could hotwire out the hollow, and then glue the offcut to the opposite side to form a curved panel. Just a thought...

 

Bad thought. Don't hotwire PVC.

Mark Spedding - Spodman
Darraweit Guim - Australia
Cozy IV #1331 -  Chapter 09
www.mykitlog.com/Spodman
www.sites.google.com/site/thespodplane/the-spodplane

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Bad thought. Don't hotwire PVC

Oops. My bad. Just a passing thought.

 

I hate bad smells...

 

Go ahead and put a car motor in your plane and spend your time tinkering instead of flying. I like to fly I tinker enough at work.

Rumour has it that Subaru started off building airplane engines, which is why their engine is this flat configuration rather than an inline or vee. Then they put their plane engine in their cars. LOTS of these things in the air and have accumulated alot of hours. Look at the RAF Gyroplanes. I might tinker for awhile...but I'd be shoving my truck down the road with it long before it ever gets hung on an airframe, and thus flatten out the learning curve somewhat.

 

This is interesting :http://www.maddyhome.com/canardpages/pages/alwick/index_files/Page475.htm

 

BTW BIg Steve - Your project looks good. I like the way you did the canopy.


Marc Oppelt

Olympia, WA

http://picasaweb.google.com/oh.u8it2

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When I built my First airplane a Longeze 20 some years ago. I thought I would be really snarky to have armpit scoops at that time only a couple of planes had them. They looked cool but I spent my 40 hour test period trying to get my little 0235 to cool properly. I am very glad I had a Lycomming because after I figured out the cooling all I had to do was fly baby fly. Talk to Buly about car motors in airplanes he got tired of his car motor because he was always tinkering now he has a lycomming and he flys baby flys. STeve build on


Steve Harmon

Lovin Life in Idaho

Cozy IV Plans #1466 N232CZ

http://websites.expercraft.com/bigsteve/

Working on Chapter 19,21

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Oh yeah, I know...alot of guys can't get them dialed in and remove them. Mostly they fight cooling problems.

 

But Al Wick details his installation pretty well, and its on a canard plane. He specifically addresses cooling system problems and how he solved them...so I'm thinking that his formula is probably pretty solid. I'd start off with a big-ass belly scoop to ensure enough air (ducted and sealed to the radiator) and then cut it down for drag reduction later. And I'd have a radiator custom fabricated rather than screwing with old evap cores and the like. No dumpster diving for de plane.


Marc Oppelt

Olympia, WA

http://picasaweb.google.com/oh.u8it2

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Pre curved radiator cores are available if you needed a larger core area to fit inside a curved cowl.

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