causeitflies

Thanks,

Even though it went quiet with my work on this, I have been on it every day other than some UAV flying for the past 14 years, no joke.
Solving the problem with the static, 2.4 ghz, I would be screwed if it weren't for that

Pegasus, you did an amazing job on the rotating nozzles and puffer outlets. Amazing!

Oh thank you, it took three attempts to get it right, there will not be a fourth.

I think Ali should buy 2 of those fan's for that 1/4 scale Mibo A-10 coming out

13,000 watts = 17.4 HP

Ewald, This is just getting more and more amazing. I have been lurking on your progress since the Tutor/titanium engine project. Scott

Yup 1 horse power per pound, the turbo fan will be over double that, good to transition into flight with.
Hey Scott, it doesn't seem to end does it?

http://www.youtube.com/watch?v=bzBoVuEQW4A

Xairflyer
Someone told me about that video a few weeks back, I have no idea who made it. Sadly its better than my videos.

Ewald,

I get out to El Mirage and Rabbit a few times a year, usually to fly turbines or test a Giant Scale Racer. I'll be out there again in the next few weeks at least once.

KennyMac

Fantastic work! Good luck with this project - it will be great to see a model Harrier hovering and transitioning to and from the hover! I have a little experience flying the full size aircraft (Sea Harrier FA2), so hope you don't mind me offering a little advice. The transition is the one of the most critical parts of flight. The SHAR used to come off the wing at around 100kts, but the newer variants (GR7/9 & Harrier 2) lose wing lift a little slower, but with either you have to ready with the power, and slam the throttle open as soon as you get the sink. Better to get the jet going up on thrust and then back the throttle off a little to hold it level, than try to arrest a big rate of descent. Can you move the nozzles forward of the hover position? Decels in the full size are usually done in the braking stop, which has the nozzles about 10 degrees forward of the hover stop position, with the hover stop being selected as the ground speed comes to zero. It's a juggle with full size controls, let alone on a model transmitter! It may be worth adjusting the rigging angle of the nozzles forward to try and get the decel controllable. I'm pretty sure, based on the time you've spent on this project that you've thought about all this stuff in great depth already, so I may be trying to teach you to suck eggs! If so sorry - just really excited to see this work! Good luck!

Hi All,

Maybe a 3 axis flybarless heli gyro for stabilisation.

BRG, Craig.

GR7Racer Once I get work to settle down a little I will let you know when I'll be out there, right now its usually a last minute decision to go out.


Pat I appreciate all the help I can get, all I know is its a very busy time when doing the transition, and having to do ruder with your hands not feet keep you even busier.
I am not set up for the additional 9 or 10 degrees forward facing nozzles but could be set up quite easily, once the nozzles and flaps are down it slows down very fast, on the video there was no forward facing nozzles so I did not put more effort into setting it up like the full sized. I figure if it over shoots a little it not a big deal for me at this point.

craigdyer All heli related gyros don't take damping into consideration due to the rotors providing this for you, so they do work somewhat but not that great. The Harrier has no self damping and this was one of the things written into the control laws on our computer. I tried a Heli Comand which is phenomenal in a heli, anyone, and I mean anyone can fly a heli with one of these on it, but completely useless on the Harrier due to no damping on it. Just one of many devices I have tried and are now lying in the corner.


Here a short ground take off video
http://www.youtube.com/watch?v=R8GM5BekffY

The hover control in that short clip looks very good! Are you going to be fitting the leading edge root extensions? These generate quite a lot of extra lift, and IMO the slower you can get the model before losing aerodynamic lift the better. Also, on the later Harrier variants, there are some strakes fitted to the lower fuselage between the nozzles when the gun pods are not fitted. They are shown in the photo:



These really make a huge difference in hover stability - pilots found that hovering with the guns was more stable than without, so they designed and fitted these when guns were not fitted. It has something to do with reducing the vortices and eddies created right under the fuselage as the jet blast from the nozzles on each side mixed. It might be worth putting something similar on your model. The other point to note is that the airbrake is extended with the nozzles down - also has a stabilising effect for similar aerodynamic and fluid dynamics reasons, but they are beyond me!

The hatch has the LERX on it, it just wasn't used in the hovering clips. Was it the weight of the guns that made it more stable or the aerodynamics of it. Do the strakes work due to all of the rising heat? Due to mine being electric there was no heat rising so I decided to leave them off to save the weight, maybe they would help me I don't know, I never tried them on the hovering version.

Reading your comment again, I can see how there would be airflow recirculating in between the nozzles, the strakes would help that. Maybe I will make a very light set and try them. Good bit of info!

Ewald,

Awesome project and I was wondering, as money others on here have said already, what was going on with your progress. Good to see your still at it. I love the size of the plane, good choice.

Those lower strakes are intended to help keep the engine from ingesting its own exhaust and stalling it. They help direct the flow of the hot gasses and keep them from swirling around and up into the blow in doors. Could be of some help on the EDF version and also the turbine version when you get to it.

The wing fence and turbulators on the top surface fo the wing manage air flow and keep it from separating and stalling the wing. You see them on other jets like the A-4 and T-45/ BAE Hawk for example. These will probably not do as much for your model unless you can prove they work through testing. Your airfoil choice has more to do with it and how your wing is designed to help you at the slower speeds approaching full wing stall.

The latest Harriers/Av-8's are so highly evolved its really good to study them closely for all of these tweaks and tricks, there is info there to be had and implemented to some degree.

Keep it going!

Chris

Thanks, my final version will have all the goodies the full sized has, whether it needs it or not, it must be done right.
Most of the tooling for this stuff is already done its just not on this version.

Thanks for the tips

Ewald,
Let me know when you are heading out, even if it is last minute. I'll try to make it and give you some help.

KennyMac

GR7Racer I will try to let you know