|Oct 02, 2011, 02:17 PM|
Ive been making progress. The wing panels are all finished building and most of the sanding is done. Just some minor touch-ups to do on them and then cover.
The fuse sides are framed up and most of the bulkheads are in and part of the sheeting is done.
I also have the rudder and fin framed up. Going to start the stab and elevator today.
Im expecting to finish it later this week
I'll post a few more pics later showing some of the changes Ive made so far. Nothing too drastic.
Slightly larger rudder and fin.
I took the angle out of the elevator hinge line and will have full span elevators with slightly wider elevator portion but the same over all size.
Modified the former in front of the wing to allow batteries to pass through and Im using short carbon rods for the rubber band hold downs.
Im going to wait until the model is mostly built and covered before I decide on servo and motor placement to check balance.
|Oct 05, 2011, 04:20 PM|
Lots of details left to do but Im getting close!!
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|Oct 05, 2011, 08:25 PM|
Joined Jun 2004
Glad you started your Mirage before I started mine. I've already picked up a couple of good ideas from you.
Where did you find an aluminum T-nut?
|Oct 06, 2011, 11:27 PM|
I got them in the hardware section of my local Ace Hardware. Tacoma Screw would have them or most any decent hardware store. Look in the section where they have all the drawers full of odd ball hardware. They are not labeled with the thread size so you need to take a sample of the bolt you want to use to get the correct ones.
The barrel on these just barely fit in the width of the 1/4" balsa ruder stick. Then I had to add the 1/64 ply to get the strength back. I ground the sides of the round "T" off to stay within the width of the balsa stick. A tiny dab of epoxy holds it in place.
Note that some of the "nuts" have screwdriver slots and the threaded part does NOT go all the way through. If you look througn enough bins you will find the ones with the holes all the way through. I prefer those so you dont need to worry about bolt length so much.
Since I dont have to worry about winch loads, Im hoping the single nylon bolt will be enough holding power.
|Oct 10, 2011, 03:06 PM|
Joined Apr 2006
Did you ever fly at Jones Field over on Topanga Canyon Blvd.?
I remember Jerry Krainok(sp?) and Dave Peltz flying a Grey Goose there along with a Sailaire. I believe they used them for some TOSS cross country contests in Taft also.
I learned to fly at Jones field in the late 70s. Dick Odle was a regular there also and bailed me out a few times. Joe Wurts was the young "kid" who was there all day long. I never progessed much above "average" and flew RES. Moved to Moorpark in 85 and flew with TOSS for a few years and flew in some SC2 contests. Retired and moved to NorCal in 1992.
Was flying EP gliders up here, but some health issues have made it not as much fun, so I have pretty much sold off everything.
Nice to see some of the old names I recognize from fun times.
MrE the EP Mirage sounds like fun project.
|Oct 10, 2011, 04:46 PM|
Boy all of you "mature" flyers are sure making me feel like I can fit right in.
Would be nice to hear some names.
Went out to the middle school today to test fly a recent Epower sailplane conversion. This is a 27 ounce two meter pulling about 70 watts at full power. Can you believe that Virginia Beach had the kids in school today. Just as I got there about 200 of them came out and started running around the field. I flew a little DLG model in the back corner of the field until they finally went back into the school; and then had a great flight with my sailplane. Nice day here today. MrE you will enjoy that mirage. -- Herk
|Oct 10, 2011, 09:20 PM|
I was just testing the motor/prop Im going to start with.
Its another CustomCDrom double outrunner. This one is a hotter wind than the one in the 2x6. Weight is 32 grams. Im using an APC 10x6 folder. Probably a Castle P-25 esc.
On 2S packs Im getting right at 82 watts full throttle, so I should have roughly 35-40 watts/pound to start off with.
Most of the "building" is done. Ive got sanding to do on the stab, rudder
and fuse plus mounting the servos and the nose block details, hatch hold down and a few dozen other minor details to finish up.
So far balance is looking good for having the packs on the CG without extending the nose, but that will have to wait for final covering to be sure.
|Oct 12, 2011, 02:31 PM|
Im getting close-er!
Wing and tail feathers are all done and covered
Whew! I hate covering second only to sanding!
Now to finish up the nose block area. Trying to decide what to do about a cowl. I may wait on that till after the maiden. There is supposed to be a hole in the rainy weather tomorrow so Im shooting to get 'close enough' by then
|Oct 12, 2011, 03:50 PM|
I decided to weigh everything to see where Im at.
Left tip = 53.5 gm
Right tip = 55.5 gm
center with servo = 235 gm
Joiners and tape = 17 gm
total = 361 gm or 12.7 oz for the complete wing.
Fuse and all other goodies including motor, battery rx etc = 382 gm
Tail feathers = 80 gm
grand total = 823 gm or 29 ounces
That does NOT include glassing and painting or covering the fuse.
Lets say another 2 ounces at a wild guess so I should end up around 31 ounces all up plus or minus.
Thats more than I was dreaming but still not bad. Im happy enough
Now back to the fuse final details.....
|Oct 12, 2011, 05:05 PM|
USA, AZ, Mesa
Joined Oct 2009
The all up weight of 31 oz. almost defies the advertised build weight of a pure glider, let alone an e-power. My calculations say wing loading is 4.88 oz./sq.ft.
Do you get about the same number, that is less than feather light. Can't wait for a flight report and photos,photos or a vid.
|Oct 12, 2011, 08:50 PM|
A lot of the weight savings comes from deleting things that are needed to allow the model to withstand a winch launch.
No beefed up spar - its bone stock per the original plan. The only thing I did was wrap the joiner boxes with some spectra fishing line. Not a lot of weight savings there but some.
The biggest single weight savings - other than the power system - is probably the push rods - Im using spectra line for those. So no threaded rods, clevises or push rods. That alone save an easy 2 ounces out of the tail - which eliminates the need for even more nose weight to balance the model. You get more than double or triple savings anytime you can lighten up the tail end.
Also - no tow hook or structural adds for it.
I also removed some cross bracing in the rear fuse and one former up front.
Im using rubber band hold down so no added weight in the wing or fuse for a bolt on system.
Plus carbon rods instead of steal for the hold downs.
I used Tight Bond III for almost all the gluing plus a little epoxy.
I also covered the wing tips and most of the tail feathers with UltraCote lite.
That stuff combined with modern micro servos and rx plus a very light weight power system all adds up.
There isnt a huge weight savings in any one place on the model - other than the power system.
The motor, esc and battery Im starting with come to 6.5 oz including prop and spinner.
If I go with the smaller pack I save an additional .5 oz.
|Oct 12, 2011, 08:55 PM|
It occurs to me that if you deduct the power system weight you get a pure glider weight of 25.5 oz - which would be extremely lite for this model based on reports Ive seen.
Thats not completely fair though. I dont think you could build a pure glider version that light.
Even moving the battery pack all the way forward, you would need still likely need some nose weight to offset the loss of the motor up front. Then add back in tow hooks and some extra weight for the spar mods everyone does plus beef up the fuse again.
You would still see the weight savings from the push rod change, so maybe 3 to 4 ounces lighter? Im guessing
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