Topic: Hawker P1091 EDf Build

Weather forecast for Camborne on Friday is currently light rain and SW'ly 25mph gusts and it is the same for the whole w/e, so not looking like flying weather at the moment.
I ran it up on the new 2650 packs with good results - detail on the spread sheet if anyone interested, but basically they are only slightly down on the 3200 60C pack and 40g lighter to boot.  T:W is 0.87 (0.86 with the 3200 pack) I will be using these packs for the first flights for sure.
 
My mind wanders when I have time off.................................

Question:

Anyone have any thoughts/comments about running a HET 2W-20 on 5S in a HET 6904 fan?

I guess the thing to do would be to go ahead and try it.

That's quite a lot of revs isn't it, 60 thousand or so. Should be interesting. I should stand a fair way off on the test run I think. Het 6904 I thought they said about 50,000 was their maximum safe rpm but there must be a margin so it might be absolutely fine. The motor I hink is OK for a Maximum burst of 55A so that might be OK too but I think you are in the realms of pushing it all to the limits and maybe beyond.
As you say Dizz the only way is to try it. I will cross my fingers for you.

That's quite a lot of revs isn't it, 60 thousand or so. Should be interesting. I should stand a fair way off on the test run I think. Het 6904 I thought they said about 50,000 was their maximum safe rpm but there must be a margin so it might be absolutely fine. The motor I hink is OK for a Maximum burst of 55A so that might be OK too but I think you are in the realms of pushing it all to the limits and maybe beyond.
As you say Dizz the only way is to try it. I will cross my fingers for you.

Yep, its all about pushing to the limits    I'm thinking of the FD2.
HET spec the 2w-20 at 14.8V and 55Amps steady, 65A burst.  The ARC 28-58-1 runs the 6904 in my P1121 at approx 54,000 rpm on 6S, so am happy the fan can take it...............I'll have a stab at working out the forces on the blade when I get home.
Anyway, think I'll give it a go when the fan arrives and just keep a good eye on the watt meter and motor temp - nothing ventured nothing gained and all that 
 

The weather beat us on Friday afternoon, but I think the field was being prep'ed for a horse jumping competition anyway.  Next opportunity will be next Friday at Weston Zoyland with Fisty before the jet meet.
Just now I was messing with the FD2 in ACAD and tried scaling it to 105%: wing area up from 16.0 to 19.4 dm2 - ideal!     
I’ll have to re-draw all the fuselage formers, but I had to change 4 of 8 and start anew for the nose anyway.  The ducting will stay the same as the P1091 which is the same a the WW Hunter intake.  I’m still considering what fan and motor combo to put in it – I quite fancy being totally insane and going or the same 1400W set-up that is in the 1121, but I do have a pusher-fan with an ARC 28-58-1 motor that was ear-marked for the EF-16 Block IV which could be used: the next time I sit down with the laptop I'll check weights and moments.  This will be my Christmas leave build so there is no rush, but I might as well get the formers and ribs cut whilst I'm off at the moment

Today during the SBAC show at Westonzoyland aifield, Hawker Aircraft Ltd unveiled their new secret jet fighter project which has been funded as a private venture.  Based on the world record breaking Hunter Mk3 flown by Neville Duke last year to an astounding 727mph, the P1091 (the name remains highly classified) made two 3 minute flights in the afternoon which included slow speed handling checks, high speed passes and some gentle aerobatics including a big loop from straight and level at half throttle.  Believed to have a thrust to weight ration of over 0.85 on the ground, it was clear to the watching public that in the air (with forward speed on) there is even more thrust available for the pilot (Geoff White) to power through vertical manoeuvres with ease.  The aircraft was still being trimmed by company personnel with adjustments being made between the 2 flights to move the C of G aft by 10mm and to reduce the aileron roll response.  It is understood that tomorrow (Sunday) more fast passes will be completed (for Doppler speed recording purposes) and an official company photo shoot.

Colin Hunt


Staff Aviation Correspondent

Is it only me who struggled to read that without putting on a silly 1950s English narrator's voice?

Looks great though Pete - any plans to maiden the other one soon? 

Bravo looks right at home in the blue.

Is it only me who struggled to read that without putting on a silly 1950s English narrator's voice?

Looks great though Pete - any plans to maiden the other one soon? 

That was the intention Jamie, just wait for an important announcement from the Air Minister Sir Michael Hunt later this evening about the Miles M52 research aircraft. 
The P1121 will finally get a coat of satin KlassKote this week which will allow it to be handled without leaving paw prints all over the paintwork.  We were all ready to give the SR177 a go yesterday, but yet another hitch (stuck elevator) prevented it flying and I didn't have enough time to fix it ready for today.

Bravo looks right at home in the blue.

Thanks - it looked even better today against a proper blue sky with a few Cu around.  Unfortunately I mis-placed my SLR and the compact couldn't handle the pace, but a couple of the best ones below.
I'm try to sort out the Doppler and post after scran.

Tootle-pip

Pete

Congrats Pete - she looks good!
Paul W.

Pete,
Thanks for your response on your sanding techniques.
Plane looks good and flies better.  To hot here in Arizona to get into shop.  Maybe next month or October.  No fun flying either due to the fact if one gets up early the eastern sun will blind you till around 10 a.m. then after that it will cook you.
take care,
Albert

We could do with some of your sun over here now and then Albert - was intending to do some spray painting in the back garden this morning but have woken up to rain again.


I managed to get one usable Doppler recording: not brilliant with lots of background noise, a big CPA on the recorder and not a flat-out run (the priority was to make trimming assessments), but I get 109mph +/-2mph.  Which tallies with my predictions 


An interesting point was that once moving the T:W was definitely > 1 because it didn't slow down in the vertical and it powered through loops from straight and level with ease (when I listen to the recording there are some some amusing comments including one from me "I have to get a windtunnel" - I think not actually).  Following recommends in the Stumax 110 fan instructions, this is the first intake duct I have done without any additional openings for ESC cooling, motor wires, etc in order to build dynamic (pitot) pressure ahead of the fan face.  I had a good long chat with Gordon W on Sunday about this subject and he found similar gains with his Hawk when it was EDF powered.  Seems like there is a way forward with this and I'll be doing the same for the FD2 and other projects idc.
The C of G position is now correct and I'll translate the actual position back into a %MAC later for future reference.  The roll rate was very fast, as expected, but also it wasn't very stable in the roll axis, not expected.  Geoff and Jamie both found that it once roll had been started and ailerons neutralised, it continued with reverse aileron required to stop.  This has now been tracked down to poor centring (only about 1.5mm on the aileron TE at widest point) on the left aileron servo.  It is a real pain as they are brand new HS125MGs and are built into the wing (another lesson there - fully exercise the servos before installing).  The first hope to cure is to connect up the servo to a tester and leave it cycling for a while to see if it will "break in" - have read that this may work and some people actively do this for every servo they use.  If it doesn't work I'll either have to live with it or do some surgery.
Finally, you may wonder why I didn't fly it or the M52 myself.  Well, with the services of 2 chaps, both infinitely better RC flyers than me, willingly available for the first flights of brand new models I would have been stupid to try myself.  So again, a massive thanks to Geoff and Jamie for their invaluable help and also to the Westonzoyland Sedgemoor club for the use of their field and the excellent hospitality over the weekend. 


Now since I can't paint, I might as well design! 


Pete