Eagler's Nest
Airframes => Single Seaters => XL => Topic started by: wojtekseta on April 03, 2017, 12:42:35 PM
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Hello Eaglers!
My name is Wojtek (pronunciation Voytek) , I'm from Warsaw, Poland. It is my first post on the forum (please forgive me my english). I read yahoo group an next Eagler's Nest from years.
My LE XL and Betterhalf plans has arrived yesterday, but I don't know the numbers yet - I'm in hospital now (hip problem).
I would like ask you about use the other than 1/2 VW motor for LE XL - heavier about 20lbf. If it is possible I will try to use BMW R1200 motor without reductor. In my opinion the engine could replace 1/2 or even full VW motor. You can see my early test of R1200 on https://www.youtube.com/watch?v=SEC5YOuWetc . I'm sure the engine has big potential - 55HP / 3600 with weight about 120 LBF with oil, carbs, exhaust and dual ignition.
If you are interested, I will explain my thoughts in new thread in 2 cylinder section. Please just let me know.
But main question is in the thread title (I know I will have CG problem and have to move wing).
Thank you in advance for your comments
Wojtek.
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In this thread please help me with my main question - thanks.
Tomorrow i will create the thread about the engine (here in Europe is late especcially in hospital).:emoji_u1f614:
Wojtek.
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In this thread please help me with my main question - thanks.
Tomorrow i will create the thread about the engine (here in Europe is late especcially in hospital).:emoji_u1f614:
Wojtek.
Wojtek,
I'm rather certain it would be near impossible to make US part 103 weight.
However it should be easy to meet EU rules.
Get well soon. :)
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Dan,
Thank you for your good wishes. :emoji_u263a:
In Poland exist two categorries where LE XL can be located:
- airplane with MTOW under 300 kg (660 lbf) - building under gevernment agency supervision - pracitically impossible. Polish builders builds aircrafts under Czech supervision :emoji_u1f623:
- powered flying device with empty weight under 115 kg (254 lbf) as US Part 103 - building without ANY supervision, but the device can be checked if fullfils the requirements of regulation.
My XL must weight under 115kg dry. If it will be impossible with BMW I will build Betterhalf.
Wojtek
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Do you have a weight allowance for a recovery chute..?
BMW is a nice engine.
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In first case (MTOW to 300kg) you can add 15 kg for recovery system, in second case (empty 115) - not.
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Get it inspected with a half vw...change to the BMW later :emoji_u1f608:
I have a feeling if you build a a strong half veedub 82 stroke x 94mm pistons, you'll enjoy it just fine and won't bother with anything bigger.
The Verner 3 vw radial looks to be a great option if you have the funds.
Good luck on your recovery.
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Thank you Dave :emoji_u263a: ,
If I will have 1/2 VW then I will use my R1200 for Airboat :emoji_u1f61c: .
Verner Scarlet 3? She is beautiful and in my opinion perfectly suited to the nature of the LE. But she has to have a huge propeller - what about the ground clearence? In my opinion the chassis should be redesigned. Cost of the engine in my home should be comparable with Hummel 37 HP with transportation and customs.
Betterhalf construction is a pretty big and complicated project, availiabilty of parts (tunning parts) in Europe is worse than in the USA. Time, shipping costs etc. But If I will not be able to slim down the airframe, I will build it.
I',m in home now and started analising plans (LE XL-G-19 :emoji_u1f601: ) and I see that will be very difficult to substact 20 lbf from the airframe.
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Wojtek...if you need a 2 cyl VW converted engine, I have one for sale. I will ship worldwide.. Email me dwstroud at xplornet.com if interested. I will go with the 3 cyl Verner with a slightly larger plane ( Model 70 Monocoupe replica ) as we have less restrictions in Canada. It is a good professional build and Scott Cassler has been involved with it. Electronic and mag for dual ignition.
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Glad you're out of the hospital quickly.
The Scarlett really does appear to be an outstanding choice. I wish I could afford one...I'd install it yesterday! Longer landing gear is about the worst of the needed modifications. Well worth it for the added thrust of the bigger prop. Check out Franks XL thread in the XL subsection. He is building with the Verner and I think we're all anxious to see it fly
:emoji_u1f600:
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Dave Stroud,
I answered PM
ArcticDave,
I'm also watching the Franks thread and I'm looking forward to a successful first start.
Concerning weight savings - I can replace BlackMax wheels with brakes with BMX wheels without brakes (should be few pounds, but I don't know how many). I think I can do lighter rear suspension (composite or aluminium). Tube struts in place of streamlined? Aluminium fuel tank? Lighter instruments (I can do electronic speedometer, altimeter, engine instruments).
What do you think about that?
What more?
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Tube struts instead of the streamlined ones save around 8 lbs by what I've seen reported. I'm not sure of the wisdom of doing anything to lighten the tail area. CG is pretty far forward as it is and these birds seem to fly(and land) better with CG around 30% of chord. With a 20 lb heavier engine that problem will only get worse unless you move the wing forward...or add weight to the tail. Oratex for covering may save a bit of weight too. It's cost prohibitive for me, but you're much closer to where it's made, so it may be cheaper for you.
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My main goal is to go down with weight to 115 kg (254 lbf) empty to fullfill the regulations. Additionaly I will build from metric tubing (fuselage + 3 lbf) that's why I need savings in any place of aircraft. I know that, I will have CG problem. I will move CG of engine possibly back in comparison with Betterhalf full case. It will be not enough - I will have to move wing forward.
It is very good info about 8 lbs of difference only on the struts. I think, on wheels should be even more , but I can't find info about weight of BlackMax with brakes (classified information?). Maybe someone knows?
I used Oracover when I was building models, even then it was expensive :emoji_u1f601: . I will use Dacron, 3M Scotch Weld, Latex primer and Acrylic latex paint. I made some sample almost 2 years ago and leave it out of house. Before I use the process on the plane I will do fabric test on the sample. The process is easy and smells good :emoji_u1f601: .
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Les Homan has a thread here somewhere that contained a weight list of various parts. It had the weights you're looking for. A search may pull it up.
I'm with you on the latex. Doing the same here.
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Many years ago I built a SkyPup and used dacron fabric from the local fabric store. Dirt cheap and it worked fine. It's the stuff you'd line a suit jacket with. Easy to work with, glue and shrink. Lots's of area to glue the wing fabric too. The ribs were 3/4" thick styrofoam.
A buddy of mine recently covered a Tailwind with the Stewart system fabric and used the latex process and it went well.
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Les Homan has a thread here somewhere that contained a weight list of various parts. It had the weights you're looking for. A search may pull it up.
I'm with you on the latex. Doing the same here.
I found it! ( https://www.eaglersnest.com/forum/index.php?topic=155.msg547#msg547 ) This is really what I was looking for. Thank you very much, Dave. BlackMax are lighter than I thought, but with BMX wheels I should save about 8-10lbf .
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Many years ago I built a SkyPup and used dacron fabric from the local fabric store. Dirt cheap and it worked fine. It's the stuff you'd line a suit jacket with. Easy to work with, glue and shrink. Lots's of area to glue the wing fabric too. The ribs were 3/4" thick styrofoam.
A buddy of mine recently covered a Tailwind with the Stewart system fabric and used the latex process and it went well.
I tried to find the other dacron, but didn't found. Price of noncertified dacron in aircraftspruce.eu is acceptable (~$6/yd) - i'll buy from them, as some other materials.
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How about $4.35/yard
http://www.aircraftspruce.com/catalog/cmpages/peelply3.php?clickkey=5724
search under dacron or peel ply if you don't find it listed as covering.
It is not perfect, may have some slight blemishes.
Sometimes the fabric store dacron is pre-shrunk,
while an advantage for clothing,
a disaster for our use.
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Tom - I know, but it is in the USA. In Europe I will buy http://www.aircraftspruce.eu/dacron-fabric-1-8-oz-x-60--611.htm . I think it is the same fabric, but for the other price :emoji_u1f624:
Once I bought 4130 tubing for samples, welding training and load tests from aircraftspruce.eu . Prices was very high ( FIVE !!! times higher, than metric tubing from 25CrMo4, which is exact european analog of 4130). I thought I will receive american tubing, but when I read on them "Made in Germany" i called to AS.EU. They said, that they import german steel from the USA. Aircraftspruce.eu is located in centre of Germany. :emoji_u1f602:
I think the Dacron could be "Made in Europe" to ...
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I'm trying to estimate the impact of a heavier engine on location of the CG. I looked to my set of plans and found, in my opinion, incosistency between sheets C, D and description on text page 11 ( empty weight + pilot 255 lbs or 275 lbs , with or w/o gas and oil ). For example: from sheet C empty weight = 246, from sheet D pilot = 255 (in text decription 275), gas = 30, oil = 4 and sumary is 507 lbs. Maybe I'm wrong or I omitted info about corrections? Could you tell me please, was it discussed on the forum?
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It seems we have to try harder and harder to find the true source of our supplies. Before ordering my 4130 from Aircraft Spruce Canada, I got a very favourable quote from a steel supplier in Pennsylvania and he said it was genuine made in Germany. The price was about 85% of ACS. In Europe, I would try to source direct from Germany or equivalent.
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It seems we have to try harder and harder to find the true source of our supplies. Before ordering my 4130 from Aircraft Spruce Canada, I got a very favourable quote from a steel supplier in Pennsylvania and he said it was genuine made in Germany. The price was about 85% of ACS. In Europe, I would try to source direct from Germany or equivalent.
I can't find the source of imperial 4130 tubing in resonable prices in Europe. If I will build, I will build from metric 25CrMo4 tubing. It will cost about 3 lbs heavier fuselage.
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The bulk of 4130 I bought from Aircraft Spruce was German. The rest was Promoly from Plymouth here in the States.
The German stuff is stamped "Benteler" and it appears to be the name of the manufacturer.
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I can make some conclusions. Teoretically the answer to the question of the subject is Yes.
Some savings allow me to remain within the limit of 115 kg, but the margin for deviations from the plans is small. With R1200 in place of BetterHalf CG should be about 25% of the chord, what Leonard somewhere described as "good start point" , but XL flying collegues write that best CG is at 28-30%. To do that I have to move the wing 2 inches forward, or put 7lbs ballast on the tail.
Excel with wieghts and CG.
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Do you know how much thrust the BMW will produce ?
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Do you know how much thrust the BMW will produce ?
I have not finished my tests yet ( https://www.eaglersnest.com/forum/index.php?topic=1525.0 ). From charts looks like R1200 should turn to 3600 rpm similar propeller as 4 cylinder VW1600 and should produce similar thrust. At this point it have about 40kW = 53HP. I belive, when you tune the engine to work at this point, it could be even more. But for LE XL I plan to use heavier propeller, which limit rpm to 3200-3300 (45HP) because of endurance reasons. My fuse will be only 10 - 15% stronger than built per plans. I hope the balancing shaft will prevent vibrations in this rpm range. In previous versions of BMW boxers it could be a problem.
One thing we have to remember, BMW is spinning in the opposite direction than front drive VW. You should use propeller for flywheel side drive.