I had this idea last year when I built this one. The problem on speedbrakes on the gear you could only use half the SB because it would stick down when the gear is up. If you compair the speedbords on the BVM Bobcat, the gear folds straight back unlike the Stringray.I am thinking on my second Stringray that I am building I might put Pop up speedbrakes on top of the wing.using spring loaded air-cylinders.Something else I encountered was I needed a Lot of deflection on the elevators to brake ground,I wounder if the CG could be moved
forward about 1 inch, We will see. Paul JPOFL:idea:

You can do the struts without retracting aft like a BobCat. JPO, it sounds like you just needed some positive incidence on the ground.

I've to wait about 3 month to fly mine, so i will wait for you guys putting some pics here of how you made it. I have a good idea how to do it ( woketman way). My concerns was about the nose strut not able to 'push' the panel. but it's probably just a question of size. Thx for the info.

Most of the retracts that I've used over the years will be able to push the nose panel all the way at least just before touchdown when the aero pressure is lowest.

Hey guys, I am finally back, been real busy and have not had time to build. I will be working on the speed brake tonight. I think I am goint to go the air cylinder option on the top brake and probably the bottom as well along with some attention in the hinging. Woketman, about how many sq in do think would be suffiient for a brake on teh bottom with out overdoing it?

Chris

I'd put about the same amount of square inches on the bottom as the top speed brake has. That should be enough. I would not worry much about over doing it too much as you can always reduce the deflections. Just don't get carried away!

I like JPOFL's solution, as the speed brakes can be operated independently from the gear, when taking off for example. Or, will the speed brakes actually improve take off?

I guess there's a chance they may improve take off due to some dammed up higher pressure air in front of them, but a StingRay with a 12 pound thrust turbine should have absolutely no problem on take off. Speed brakes or not. Plenty of thrust.

Well I said I needed alot of reflexion on elevator to brake groung, Someone said I needed more up incs. on my plane. The wheel cutouts and same with the nose should make it a no brainier. My Second Stringray is sitting in it's gear with wheels. I am using BVM 2 5/8 on mains and 2 1/4 on nose and I have a
positive 1 3/4 degrees. I think it needs at lease 4 degrees. Any opinions? I am also thinking about enlargeing the elevons. I even think I still have several canards left and that might be something to consider. Paul JPOFL

JPOFL,
Do the offsets on your struts (mains) hang out of the bottom of the wells into the airflow?
The recommended gear are straight robostruts, but I like the look of the offsets.
Thanks,
paul

hey crashmaster, I will be using offset struts in mine but the offsets will be on the inboard sides and they will clear so the doors can close. Paul, could you post a close up pic of your speedbrake linkage please. I almost have mine figured out but would like to bump my installation against yours. I have made a couple of very small changes and additions to the linkage and hinges. I have to shave a little off of the trailing edge of the speedbrake so it will close all the way, it hits on the fuel cells, anyone else having this problem.

Chris

Here you go Chris. This is the same as my Org. but I did not cut out the bottom of the fuse. When closed they lay almost tight to the bottom.I will post a second picture right behind this one.Notice I did not use offset struts on this one I used straight BVM Dura Struts. Paul JPOFL

Chris Something you need to keep in mind is when you use the fuel tanks from Jet-tec there is very little room left underneath the fuel tanks. This is why I wanted to keep most of my SpeedBrake setup on the outside of the aircraft. Paul JPOFL

I am sorry Chris You did ask for a picture closed. Notice I used a brace on the outside of the pattels to keep them from twisting side to side. If you make a fork out of a piece of composet met.
The fork will slide onto the bulkheads just in front of the wheels to help support the SpeedBrake. Good Luck

Paul JPOFL

Thanks Paul, I was actually talking about the top speedbrake, sorry for not being more clear. I do like the idea you used on the bottom too, I am not quite to that stage yet. I am hoping to cut a brake out of the bottom and use an air cylinder as you did but mount the cylinder inside between the wheel wells or put the brake in front of the tanks to hopefully counter the nose down pitching of the top brake. As you can see, I am still very much undecided in the method that I am going to use.

Chris

Top Speedbrake is not used on my model it is just a hatch for checking fuel etc. Sorry I found it ineffective. Thanks Paul

My almost completed new AD F16 Falcon.

Now that is a great looking Falcon Paul!

I'm working on it. No Clear yet working on detail.This one has Ailrons. and full scale lighting.The colore and markings are scale.
The full scale bird belonged to the Royal Netherlands Air National gard, Squadron 322, in 1993.That particular aircraft was the 50th anniversary of 322 Sqn.If interested check out this link. Thanks Paul jpofl

http://www.322squadron.nl/index800.html

Is this the real thing or not. JPOFL??

Paul,

Great looking Falcon! Can I get a closeup of the gear? What did they cost?

Shaun

Hi Shaun. Here is a shot with the lights on, Paul JPOFL

Ok, after a week and a couple cases of beer, I finally made up my mind on the upper speed brake. The actuation linkage as recommended by the kit I did not like because it was limited on the throw that I was able to use and it also was going to interfere with the kevlar tanks so I changed it to something that I think is going to work, I feel that the linkage hookup to the hinges may be less than desireable but I have 110 oz of torque and metal gears so hopefully all will be well. When I glued the hinges to the speedbrake there was some torsional twisting between the two hinges so I machined some supports that tied the two hinges together and it made quite a difference. The only play that can be made in it know is airframe flexing which I hope will be diminished after more construction is done and the thing is stiffened up, but really how much stress is going to be on the brake at landing speeds anyway???, I hope that I am just being overcautious. I will add the lower brake after I get some of the internal equipment installed and then work around it. Here are the pics, tell me what you guys think. Nice F-16 Paul!

Chris

a different angle

closed

and open