Life has thrown me a curve ball-- a small stroke just before Christmas. So a need for a minor change in my building. The Sabre is on hold for now, low on cash and not yet able to do the detail work I need to finish the sabre. Right arm not up to it yet! So I thought I would try a scratch foamy.
Had been looking for a subject to model, and had seen one that Hoover or die had built. I too have always liked the lines of this plane, just as Hoover or die did. His thread http://www.rcgroups.com/forums/showt...ght=e+scorpion A good 90mm size. i did get a start on it before my stroke, whch as it turns out, was a good thing. The one from Aviation Design is Length =59" WS= 49" , mine will be 60" long, WS 52", just a little bigger.
Looking at cutting cores for wing. stabs, and tails. Using FFF for most all else. Guessing AUW around 10lb or so, so needed a little larger wing area. JetFan 90 / Het 700-68-1200KV 12s, Rhom-air retracts. Had thought 1680Kv on 8s might be OK, but our field is grass and the extra power won't hurt. 12s add about 1lb more, but close to 12lb thrust, instead of 9lb. Worth the penalty, I guess. I do need to get a few things, but it will not break the bank. I did have all the templats cut for air foils and plans drawn up. I could not do that now. Any way here's what I have so far. I am afraid this build will take awhile, not as fast as I once was!
Now I just have to clean my work area. Left it quite a mess when I had...Continue Reading
I already have the fuse done, and glassed. Now I need to fill in the imperfections,finish the prep stage, and will be ready to pull a fuse.
Concerning the Starfire, with the new JETFAN 90 able fly 16lb planes very nicly, I may look into modifying the plug for it. Think of it, a Starfire with really small intakes!!!
Would also be much lighter, difference in just the fans is 1lb. The old OS91/Dynamax system flew the Starfire for years at only about 12-13 lb thrust. The Jetfan has almost as much, and with pulling my own fuse, it doesn't have to be built like a tank. Food for thought.
Progress is slow, but it's starting to look like a Starfire!! To get the wing and stab fillets just perfect was quite a chore. It was a lot of fun trying to get 5 seperate axis all at 0 degress at the same time. But I got them .
Just a quick pic or three It's still pretty rough, but after all, it's only the plug. Next, I need to install tail fillet, cut out hatch and canopy area, and cut out intake areas.
Tail to be glassed on after the 2 halfs are separated from plug and glassed back together. Along way to go yet, but at least it's starting to look like a Starfire!!
Note: For those of you blowing up the pics, the "specs" on the foam blocks are from hard foam insulation. It's not your eyes!!!
Got the rewound motor back from Lee on Wed, 28th. Time to assemble. All went together as expected. I spent I great deal of time lining up all the right parts, and now that it's done, it's kind of a downer. BUT, on the up side, I have, like many of you, a 3-day weekend to look forward to. Clean up the work area, and get back to working on the plug. Happy New Years, to all.
Here's what Lee came up with---
Hey Mark, well the motor did fine, but the ESC flamed after running at 130a for a only a few 30 second runs.
The voltage on my Turnigy 25c lipos was dropping to about 3.4v per cell, for a total voltage of 41v. I was planning on testing by using 12s2p so that it would hold at 44v, but the esc didn`t make it that far.
On 12s 25s 5000 cells the numbers were
This is going to give about 15lbs of thrust and about 220mph efflux
On really good lipos that will hold 44v it will be more like.........
240 efflux aprox
That`s all I can do on the testing. That was the only big esc that I had.
Thanks to Hofer, who has provided a great deal of info and measurements. Were on to the filets. The plans you get from Y/A have (zero) measurements, and are not to scale. So a great deal of thought and measuring needs to take place first. the old saying, measure once, cut twice doesn't apply here!!! For the stab insert, I cut 2 different airfoils, one at 100% the other at 106%. This way when I get the insert squared, and incedence set, I can line up the 100% template, and sand it to get a nice tappered filet. The tough part is to get a -5* on each side to get proper anhedral. Wing will be same method, but needs 2.5* dihedral each side. I got this far, just another hurdle to jump.
Got word today my adaptors are made, they look sweet. Going to send Knife Liddle my motor for a rewind and make it a 695KV. Hope to have them both back and Dynamax put back together by Christmas. With this stand-off mount, it should get max cooling! That will be MY present!!!!
Started this a little while back. Have been doing research for well over a year. I have read just about every thread about the Starfire, here and at RCU. I do have just about every photo posted that will help in the building process. My big brake came 2 months ago, when, I PM'd a guy that was doing a build, and was going with a turbine install. I asked if it was possible go get a copy of plans, and ended up with the plans, full manual, and all ducting, for the price of shipping. You can't beat that. Two years ago, I bought a OS91VRDF/Dynamax & pipe, thinking one day will have to do something with it. I know its old school, but it's a start, and by the time I get this done, will more than likely have converted it over to EDF. Lots of good options coming soon. Even heard Tom Cook is working on V.2 of the Dynamax.
Just recently have started on plug. First thought was to do lost foam method, but in PMing a few helpful guys, it looks like it's possible, when plug is done, to use packing tape over plug, wax, PVA it, then glass it.Should be able to salvage plug for one or two more pulls. Will see. Progress is and will be slow---we all know extra cash for most of us is a little hard to come by. Here's a couple of pic's. Needed a PS for foam cutting--so I built one. That's the transformer under the grill. Weighs about 4LB's. Works great, 24V,4A almost too much power. And a couple of plug. Still in the shaping stage.