Ultimateīs electric Grand Esprit - RC Groups
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Oct 18, 2017, 09:05 AM
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Build Log

Ultimateīs electric Grand Esprit


Hi friends, let me share with you all my actual fall and winter project, a scratch built Renaudīs superb Grand Esprit. Rather than be a exact reproduction of his fine design we wil do our personal aproach and it will involves many ideas not mine but sharing with sailplaners of RC Groups. Mainly the mods will be done on the wing and tail... on the fuse we want to be more conservative and will follow more close the original designer idea with the pod and boom idea using a nowdays carbon tube instead of the original fiberglass and the front of the fuse will be changed to a electric propulsion but will try to preserve the outlines to the maximun possible, only these will be changed a little on the wing tips to install the also from Master Renaud Hoernerīs tips shown on his Aquila and O2 and so on the V tail tips too.
On Sailplane Talk there is a superb thread for the Grand Esprit were many talented sailplane lovers shown amazing ideas and their personal touches to this ship. Friend Ed; ( Cloud Cruiser is doing and awesome redesing of this ship with many modern touches and updates and kindly he let me use many of his ideas mainly on the wing plattorm, structure and airfoil; a Selig 3014 instead of the original Naca flat bottom ). Have many ideas about linkage for the tail and do a removable one even on two halves. On my club, friend Agustín did last year another GES more traditional only with mods for electrict and thatīs a good choice to compare performance between the original and actual ideas ).
All you are weilcome to participe and really glad to have your experience with this ship. When I was a kid that was my dreams ship but never could afford, built some others of Master Renaudīs desing but couldnīt build this one. Nowdays the few kits avaliable have astronomical prizes on the web and is a good news than Skybench plan to rekit the Airtronics kits but for me itīs a little too late... so I started some days my aproach to this gentle and vintage beauty...
As said after download the frien Edīs wing plan and printed I started to trace all the ribs pattern, so what I did before is to glue the ribs outlines on papercard, cut out and trace with a fine point sharpie over the balsa sheet trying to save the most possible material. Rather than 1/16 balsa sheet we choosed to use 1/32 inch....
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Oct 18, 2017, 09:15 AM
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Slots for the spars must be moddifed a little cause weīre going to use 10x3 mm. tip quality pine spars.. this will give us enough room to use a 1cm. carbon tubes and 8mm. carbon joiner rod inside the main spar and the 3mm. spars will give inside the right amount of center dihedral neccesary if the tube touch on one inner side the top of the upper spar and also touch the inner top face if the bottom spar and it goes on lenght till the fifth root rib..
Oct 18, 2017, 09:18 AM
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A sharp fresh single edge blade and a ruler was used to cutting all balsa ribs... there is anothers more faster aproaches to doing ribs but i love to take my time on each rib and give all necessary time to do the job the better that I can do it, Iīm not on any hurry cause this is a long time wished project and even the flight is the best reward to these projects, the time spend on the bech is also second to none..., spend some days tracing, cutting and adjusting each rib, false rib, trust rib and so but at end the cutting rib job is done...
Oct 18, 2017, 07:17 PM
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Thanks Manolo for starting this build log, it will be enjoyable to see it come together! Ed
Oct 19, 2017, 04:12 AM
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Wow. Great model pick. Be following this one.
How many gliders do you have now?? Lol.
Oct 19, 2017, 08:56 AM
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Quote:
Originally Posted by ultimatetwo
Rather than 1/16 balsa sheet we chose to use 1/32 inch....
The rib photos look more like 3/32?
Oct 19, 2017, 09:35 AM
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Tx so much for your kindly words and support buddies...I apreciate a lot. Tim have eleven sailplanes, most of then vintage all balsa, three Bob Martin Slopers and one Hacker Vagabond foamie, but considerer than many, like the Aquila have 40 years and still cooking de pure sailplane version...as one is rather nostalgic thatīs the reason why love to build and fly these woodies...
Ed... Iīm sorry... youīre right balsa ribs width is 3/32, ( over 2.5 mm.), not 1/32.., excuse my mistake buddies... as said before, the pine 10x3 mm. spars give us the room to use a 10mm.O.D carbon tube with a 8mm. I.D. to enter the same material rod. after we cut all balsa ribs we begin to saw the 2mm. Findland, aircraft grade plywood for the center reinforcements , not still totally finished the rib cutting cause now we must to mods some of then for the spoilers and servo operated cable routing...
Oct 19, 2017, 09:46 AM
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We keep all ribs separated by each half wing on stacks and rubber bands plus plastic bags... this way is a lot of better to organizate the stuff.. at least for me. For the root ribs and the others one use to form the sort of karman on the fuse we preffer to use 1/8 light ply cause is better to sand and match the wing halves with the fuse.. we are going to cut six ribs of these instead of four cause for the fuse we will use two ply ribs glued togethers on each side, itīs to say a karman root rib of 6mm. on the fuse that will let us more latter when building the fuse to form nice fillets around that will keep the vinil tape used to secure the wing halves close to the fuse...ala Aquila style...
Oct 19, 2017, 09:54 AM
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After all ply root ribs were hand saw we spot glue with some ciano to form a stack of ply ribs... this way more latter we will drill the holes for the joiners tubes and spoilers cables on a vise and that way will insure that holes and ribs will match and help on the alignement of wing-fuse process...by the way now itīs a good time to cut also a tool to check the trueness of the profile when sanding...
Oct 19, 2017, 02:20 PM
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Subscribed (and to Cloud Cruiser's thread on his modified Grand Esprit).

This summer I lucked into buying a retired Grand Esprit (mechanical mixer, etc.) and found an unused Airtronics/Cox canopy for this (and other Airtronics models) in my stash so I'm thinking about eventually building a electrified GE.

I've read some of your builds and I think we build in very similar manner. I use an Ajusto-Jig extensively and recently scored the bare bones wing jig components for a second one at a local swap.

I probably will use a carbon reinforced wood boon as importing stuff into Canada these days is pricey both due to shipping charges and currency conversion vs. the U.S. dollar.

regards,

Michael in Ontario, Canada
Oct 19, 2017, 03:35 PM
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Hi Michael... welcome to the thread.. great to know that you have an GES..please no doubt to post whatever you consider helpful... my idea about fuselage build is go close to the original desing with some minor mods... maybe a inch. or less longer on the front, not much and use a carbon boom from a Supra clone ... the sizes match almost perflectly with very little mod on the the pod and boom joint... lots more stronger and light than original fiberglass tube and this way preserve more the original looks... had also a Aquila and GES canopy that got from a forum buddy and another Isthmus Models Mirage canopy.. this last one I used on my electric Aquila version cause itīs more streamlined than taller and rounded original that is superb as pure sailplane, but maybe for a better folding prop action the first one should be better, not sure yet.. when we achieve that stage then we will see best match...
Best regards.
Manolo.
Oct 20, 2017, 10:46 AM
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Quote:
Originally Posted by ultimatetwo
...we will drill the holes for the joiners tubes and spoilers cables on a vise and that way will insure that holes and ribs will match and help on the alignement of wing-fuse process...
An alternate to the spoiler cables is to mount 9-gram servos in the wing. I did this on my Oly 3 and also constructed a "piano" type hinge from very small aluminum tubing and music wire. This mod might be a faster, stronger way to get the spoilers done. Ed
Oct 21, 2017, 06:38 AM
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Quote:
Originally Posted by CloudCruiser
An alternate to the spoiler cables is to mount 9-gram servos in the wing. I did this on my Oly 3 and also constructed a "piano" type hinge from very small aluminum tubing and music wire. This mod might be a faster, stronger way to get the spoilers done. Ed
Absolutly Ed... thatīs what I want to said... for the servo spoilers cables, just measured the connector and did the holes for routing... as you said my idea is use two micro servos one on each operated spoilers and the K.I.S.S. way to operate, no pushod but the own moddified servo arm open and close the blade, a little magnet to keep blade down and closed..even on inverted and a screw to adjust the blade flush with the top surface of the wing...used this way on all my thermal sailplanes and goes without any issue.. ( Keep It Simple Stup..).

https://www.rcgroups.com/forums/show...nversion/page7
Oct 21, 2017, 06:41 AM
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And letīs go a little bit with the wing framing...we cut also from a scrap of ply a gauge to give the root rib the right angle and also cut this 5 degrees angle also on the face of the ply shear webs that match with the root rib...did the notches also for the spoilers bay and weīre ready to start the true building... need to cut the plans for a workable use and put on the table board and protect it with wax paper to avoid glue sticking into the plans and easy removing the frame.. now is were begin the fun..
Oct 21, 2017, 06:44 AM
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Using the same full ribs as pattern we pinned the 1/16 balsa sheet bottom TE and LE sheeting... also using the notches of the ribs we glued the bottom spruce 10x3 spar on position...We used medium ciano to glue the bottom spar and ribs but not glue still the bottom front of ribs to the sheeting cause we must shim the sheeting on this area and will do when all ribs will be glued.. the shaped TE 31x8x2 mm. balsa longeron that plan to use as spoilers blade is perfect for that step of raising the bottm sheeting on the front..also start to add the healthy 10 mm. wide full shear web using a scarp spruce spar and the own ribs as template trying to achieve the most precise cutout and match..
Last edited by ultimatetwo; Oct 21, 2017 at 06:51 AM.


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