GliderIreland - Ireland RC Forum - Flying Model forum in Ireland
Gliders => Slope Soaring => Topic started by: rasemote on October 31, 2011, 09:39:38 AM
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Hello as Spoke about it Fred I open a comment on Kostez not to disturb the comment of the QUARK thierry one or two link for Kostez
http://ludovic07g.blog4ever.com/blog/forum_msg-227569-99251-262149-1.html
http://www.dailymotion.com/rasemote#videoId=xk241s
http://vimeo.com/user4308664
:D :D(http://www.gliderireland.net/forum/images/uploads/rasemote/1%20fuselage.jpg)
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I'm looking forward to progress on this thread!
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Hi John/Fred
As a matter of interest what weight are those fuz,, moldings??.
(The ones molded here).
Brian
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Hi Brian,
I'll weight mine tonight and let you know.
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Hi Fred,
Ok thank you.
Was your one made here or in France ?
If in France maybe somebody can weigh one made here as well.!!??
Brian
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Hi Brian,
Weighted mine (made in France of course :mrgreen: ), and fuselage dry weighted at 1.350kg :D
Note that to build the Kostez entirely, only 1kg of resine is used!
But once again, that depend what you want. A 4m aerobatic glider don't need to be that light (and you have lots in this range of sizes, like the Alpina etc), but for a VTPR glider, yeah, no other choice!
I think my second fuselage is 1.5kg dry, but to be honest, at this size, a 2kg fuselage is not the end of the World, especially in our slopes and with the type of wind we have.
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Hi Brian/Fred
I weighted my fuselage tonight and it is 3kg. I used a heaver glass cloth than Fred (210g) and I also got extra cloth added to areas for strengh ( nose, tail, thin area of fuselage in front of the fin, and also where the wing tubes will be located. If I can kept the model under 10kg (4.5m wing span) I will be happy.
I could have made it lighter, however, with poor landing areas on most of the slopes we fly off, a lighter model would not last to long with my standard of flying :oops:
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Hi Fred,
Thank you.
Do you know the wing area ??
I ask because I am working (early stage) on an own design 3m aerobat !!
It is something that I have had in mind for a number of years now and seeing the Kostez brought it back to mind.
Brian
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Hi Brian,
No, no ideas, just it's big! :D
I'll check that tonight, but you can't really compare the Kostez to a 3m WS glider. My 3meters Quark is big, but compared to the Kostez, looks like a hlg :lol:
John, 3Kg seems "normal" weight for this size :D
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Hi Guy's,
Thank you.
I know it is not really the same.
However I have some experience of 1.5 to 2m aerobats .
I think if I can get the area right (small cord changes at a span make a big difference) for the right weight I can do do something 'new' that will fly 'big' at a size that is reasonable to handle/ carry /launch/transport etc !!.
Wing loading is wing loading !!!
I have had an idea for a fuz for a long time so we will see !.
Brian
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Hi Brian,
Looking forward to it :clap: :D
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Hi John/Fred,
I'm just sticking down a few thoughts/figures for reference.
My understanding of a 'good' VTPR model is that it should be light, whatever that is ???.
The French Kostez's are 7.5/8 kg.
On the RCG thread they said they were 60g/dm\2.
My Voltij (all glass-heavy'ish) is 46g/dm\2 @ 1.65kg for a 2m.It flies good but needs some air.
The Limande is approx 40g/dm\2.
It is likely that there is a threshold wing loading where these planes go from being good (agile/lively/efficient with good energy retention) to being not so.
I have no idea where that threshold might be.
We have to be careful about adding weight for strength as the weight can become the source of the problem, eg for landing.
At an impact the energy involved is a multiple of the weight and the speed - ironically the heavier the wing loading the faster the landing/impact (normally/as a rule).
I am going to aim for 45 to 50g/dm\2.
Brian
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Hi Brian,
Wing loading is only one thing to be taken into account for a VTPR capable machine (for info, the Brittany machines are below 40g/dm2).
Static moment, profile etc etc is as important, and that's the difference between an aerobatic glider, and a VTPR glider.
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Hi Fred,
I am just trying to explore this subject a little bit more - for me and for other pilots that have an interest.
By static moment do you mean tail plane position relative to wing cord - ie; tail moment ??. If so do they have longer than normal or shorter than normal gliders.
So the Kostez at 60g/dm\2 plus is 'outside' the normal wing loading for VTPR. I know it is big and that weight does not scale up pro-rata with size.
Brian
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Hi Brian,
Not to sure how to translate that, but that would be the fuselage moment (by itself), basically where in the fuselage the most lift is generated. not to be compared with were the stability is most generated (usually at the CofG of course)
Position is critical if you want a glider that perform well on knife edge (without much, or in theory without rudder input), and is about 15 to 25% from fuselage nose (just look at all the proper vtpr glider fuselages), the tail of the fuselage generating almost no lift (your fuselage tail can be a stick, that will not change much the knife edge performances)
Then, you need to select a good profile that will work at the correct Re number you are looking for, but most specificly for VTPR, a profile that will work well in no air speed (able to do a roll with no airspeed for exemple). You can have a look at the TP series, and of course, the good old SBs. All these profiles work with a certain size of ailerons etc etc
Anyway, all that is only computer theory, you will never match the speadsheets performances of a profile etc with a build, even Boeing don't pretend that, but the goal is to get as close as possible to the "perfect" recipient. As Dassault says, if it looks good, it will fly right! :D
On another note, I think lots of experts are talking about VTPR gliders lately (seems to have been discovered only a year or two ago...) but most, if not all the gliders they choose, compare etc, are barely VTPR gliders in the true sense of the term.
But they are great aerobatic machines. VTPR is another league, another way of flying altogether. I flew / tested tons of aerobatic gliders, but flying a glider truly designed for VTPR, is totally a different world by just the way the machine fly and react to your inputs.
Almost all aerobatic gliders can do a roll at wingspan altitude from the slope... But a handfull will do it at zero speed! I think this is the simpliest way to describe these machines.
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Hi Fred,
I think that this is more a 'Dark art' than a science. :shock:
There is also a 'style' aspect to the Brittany type I think.
I don't like the knife edge performance unless there is huge lift.
Thank you for your input.
We should keep this going a bit to help develop 'our' understanding.
Brian
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Ah no, I leave the expert doing it on other forums :P
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Hi Brian,
Not to sure how to translate that, but that would be the fuselage moment (by itself), basically where in the fuselage the most lift is generated. not to be compared with were the stability is most generated (usually at the CofG of course)
Position is critical if you want a glider that perform well on knife edge (without much, or in theory without rudder input), and is about 15 to 25% from fuselage nose (just look at all the proper vtpr glider fuselages), the tail of the fuselage generating almost no lift (your fuselage tail can be a stick, that will not change much the knife edge performances)
Then, you need to select a good profile that will work at the correct Re number you are looking for, but most specificly for VTPR, a profile that will work well in no air speed (able to do a roll with no airspeed for exemple). You can have a look at the TP series, and of course, the good old SBs. All these profiles work with a certain size of ailerons etc etc
Anyway, all that is only computer theory, you will never match the speadsheets performances of a profile etc with a build, even Boeing don't pretend that, but the goal is to get as close as possible to the "perfect" recipient. As Dassault says, if it looks good, it will fly right! :D
On another note, I think lots of experts are talking about VTPR gliders lately (seems to have been discovered only a year or two ago...) but most, if not all the gliders they choose, compare etc, are barely VTPR gliders in the true sense of the term.
But they are great aerobatic machines. VTPR is another league, another way of flying altogether. I flew / tested tons of aerobatic gliders, but flying a glider truly designed for VTPR, is totally a different world by just the way the machine fly and react to your inputs.
Almost all aerobatic gliders can do a roll at wingspan altitude from the slope... But a handfull will do it at zero speed! I think this is the simpliest way to describe these machines.
Hi Fred,
Yes I think I understand.
In the first paragraph you are talking about fuz,, side area and side area distribution.
This is where they don't work for me.
In knife edge the fuz is the wing.
The CG should be at 30%ish, of the fuz side area.
The fuz should have a wing profile .
It should have enough side area to 'fly' in knife edge.
This side area should be effective at creating lift.
Wing profile - I agree and add that to be able to adjust camber ia good ! - 4 axis control.
For this the aileron/flap should be 30% of cord !?.
I also agree with 'a lot experts talk about VTPR gliders lately' .
I think it is a good time to try for something new - a little bit different.
I will try anyway.
Brian
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Guys
I take an idea, draw a rough plan, then build a prototype model! Test fly the glider, THEN start to make changes. Yes Fred you are right, the old saying (if it looks right, it will fly right).
I have flown many types of gliders over the years, and have
noted some good design ideas and some bad. Would it not be simple to take the good design ideas and build a great model, because if you look at the designs of most of the gliders on the market ( they look over all, the same in basic design, except for size and aerofoil section).
NASA still use models to test design ideas, so lets get building :lol:
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Hi Fred,
I am just trying to explore this subject a little bit more - for me and for other pilots that have an interest.
By static moment do you mean tail plane position relative to wing cord - ie; tail moment ??. If so do they have longer than normal or shorter than normal gliders.
So the Kostez at 60g/dm\2 plus is 'outside' the normal wing loading for VTPR. I know it is big and that weight does not scale up pro-rata with size.
Brian
hello
My fuselage at the exit of the mould made 1500 gr
for simple fact my kostez for the first flight(theft) made 7.5 for 4M
(more the glider is heavy more it is fragile)
emplanture 480 mm salmon 300
Stab emplanture 300 salmon 190
The principle of the kostez is its key of wing and its central girder if it is to respect your serat glider at the level of your piloting to see the Magazine MRA thierry
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Hi Fred,
I am just trying to explore this subject a little bit more - for me and for other pilots that have an interest.
By static moment do you mean tail plane position relative to wing cord - ie; tail moment ??. If so do they have longer than normal or shorter than normal gliders.
So the Kostez at 60g/dm\2 plus is 'outside' the normal wing loading for VTPR. I know it is big and that weight does not scale up pro-rata with size.
Brian
hello
My fuselage at the exit of the mould made 1500 gr
for simple fact my kostez for the first flight(theft) made 7.5 for 4M
(more the glider is heavy more it is fragile)
emplanture 480 mm salmon 300
Stab emplanture 300 salmon 190
The principle of the kostez is its key of wing and its central girder if it is to respect your serat glider at the level of your piloting to see the Magazine MRA thierry
Hello Thierry,
Merci !
Wing root cord ;480mm wing tip 300 !
Tailplane root cord 300 - tip cord 190 ! ??
(more the glider is heavy more it is fragile) - touche .
The Kostez is beautiful - tres beau ! but a bit too big for me to handle.
La femme petite pour moi - no big mamma !!
Bonne nuit .
Brian
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Hey Brian,
Nice translation :lol:
Regarding the size of these gliders, you have to keep in mind that to handle, it is not like a scale glider the same size.
Fuselage width is about 10cm at the max, and weight is less than half!
Big, but easy to handle at the slope for the launch.
You can see a video of the Kostez being launched alone, at walking pace.
But, transportation in / out the slope can be a pain alright!
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Hi Fred,
It is as you said transport- carrying up the slope if it is a long walk etc.
Yes I saw the vid,, of the launches.
The wind was not too strong.
I find in strong winds the 4m+ models are a handful to launch while on your own.
I am going for a 3m experiment.
F3A on the slope !!
Brian
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Hi Fred,
Here is one of test tailplanes completed, foam with balsa skin, just need to cut a section off for the rudder movement, hopefully I will get the other completed tomorrow, just needs balsa skin applied.
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/IMG_6058.JPG)
Biggest tailplanes I ever made, 1/2 m each :?:
johnp
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Nice job John :clap:
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Thanks Bill
Finished the other tailplane today, so ready to start wing cutting on the second set of tailplanes and then, the main wings.
The profiles for the wings are ready thanks to Bill, just need to cut them out and start cutting with the hot wire.
(http://www.gliderireland.net/forum/images/uploads/JohnPearson/IMG_6069.JPG)
Tailplanes ready with carbon tubes installed ( wings the size of some of my small gliders!!)
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hey john you're on fire with this building :D
things are looking good :clap: :clap: :clap:
can't wait to see this in the air :shock:
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Looking good John! :clap:
Your B52 Elevator is smaller? :?:
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:D :D
tres bien cela avance
attention j'ai pulvériser mon kostez jaune à la pente
rupture de la clef en carbone de 6 mm en plein sur le stabilisateur sniff
indeed it moves forward attention I have to spray(pulverize) my yellow kostez in the slope break of the key in 6 mm carbon in height on the sniff stabilizer
thierry
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Le carbone pour les clefs d'aile ou de stab c'est vraiment a proscrire, ca supporte super mal le cisaillement. Il vaut mieux mettre du jonc de fibre de verre, c'est plus lourd mais largement plus résistant.
Un peu trop dur à traduire pour moi
Key carbon is very fragil, prefer fiber glass key
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une dernière vidéo avant le fameux crash
A last video before the famous crash of the kostez
http://vimeo.com/32711243
thierry
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Superb,
Enthralled from start to finish.
John
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Very entertaining flying gentlemen. :D
Bravo! :clap:
Keith.
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Ouch Thierry!
Very nice video indeed! :clap:
Alright, regarding the Kostez now, anybody interrested in a Samba group buy?
Can get sheets from France, 15.5 euros / sheet.
Sheet size : 3.8m x 40cm! 1mm thick
Time to do some stock! :D
And we share the shipping, whatever the final cost is (ie, 60 euros / 20kg, will be of course less in our case, unless we order 20Kgs of Samba! :P )
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Samba?
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Hey Bill,
Like Obechi, sheeting wood. High Quality stuff :D
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tu commande ou chez air tech
si tu veut un coup de main dit moi ......
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Hey Bill,
Like Obechi, sheeting wood. High Quality stuff :D
Merci