Topic: Hawker P1121 EDF Build

Work still getting in the way during the week, but a modelling day today 

Glue setting on P1121 tail plane mod, will be able to see if it has worked this evening.   I also have batteries charged ready for tests to gather some thrust/voltage info to inform flight pack choice. 

Anyone interested in a P1154 build?

Anyone interested in a P1154 build?

I'm having trouble with the Gyro settings in mine...
Paul W.

I'm having trouble with the Gyro settings in mine...
Paul W.

Afraid it won't have a fully functioning Pegasus, will rely on a Flight Deck ramp to get in the air 

After a long lay-off due to unexpected other commitments I managed a couple of hours back on the Hurricane II this evening.  Panel lines drawn on with a 0.5mm permanent fibre tip pen – actual finish looks much better than in the photo.  I still have to finish the tail-plane control mod, but after that it can have a light coat of satin Klass Kote to protect the paint.
I carried out some installed thrust tests using different packs and was pleasantly surprised.  Nose down in an EPS foam support pressing directly on the scales, batteries fully charged with figures taken approx 30 seconds after start.  Batteries were at room temp of approx 19^oC.  On the 6S I hit 1554 Watts (just over 2HP  ) and measured the efflux at 163mph    – the exhaust air was noticeably warm from the motor/heatsink so Jamie’s derogatory comments about my hair driers are probably justified!  Here are the figures:

Pack                     Volts    Amps   Static Thrust (g)
3700 3S 35C         11.3    30.6      540
4000 4S 30C         13.4    41.3      798
3200 4S 60C         14.7    49.0      920
4800 6S 30C         19.7    78.0      1554

The graph shows a good straight line correlation.  With decent 6S 60C pack that can hold the voltage it predicts approx 1800g static thrust.  I now have enough info to make a decision on what packs to go for……………….well almost.  Last weekend I became the owner of a Stumax 110-52 that will run on 12S so ideally I would like to buy 6S packs that can power that and the P1121 – the search continues.

If only a petrol hair-dryer was available! Looking good mate, there goes the plan for the economical 25C 12S packs though if you are looking for 60 from your 6S.

If only a petrol hair-dryer was available! Looking good mate, there goes the plan for the economical 25C 12S packs though if you are looking for 60 from your 6S.

Yep, but just think what the Stumax will go like on 60C cells 

Fast approaching ICBM territory I should think, lol. Should give the glider boys something to frown at if nothing else.

I remember some guys over on RCGroups set out to beat 200mph with an EDF and it took a awful lot of time and effort but eventually they got there. Amazing to think those glider boys are doing 400mph that is just so fast, can they go much faster? 500 600. They must land and their knees keep on wobbling for a good ten minutes after.

I met up with Paul W during the week and we were able to compare P1121s.  Almost spooky how similar our two independent efforts are in size and structure, although I must say that Paul has achieved much more elegant solutions to lots of design problems.
Anyway, a dual use pack to also power the Stumax EDF is not possible, so suitably enthused I got back on the P1121 case to order the batteries.  Unfortunately my chosen XPS 65C 6S packs are still not in stock so to get things moving I have ordered 2 x Turnigy 3300mAh 30C 6S packs as a stop-gap (good price).  I do not think the voltage will hold up under load, but claimed weight is 544g so slightly lighter and I will test before attempting to fly.  I don't think they will be delivered for a week or 2, so he first flight still a long way off.

Pete

What you politely didn't point-out though, is that whilst mine is still awaiting its final scheme -yours is looking very snappy in its squadron camouflage colours! Thank you for your kind words Pete!
It was very good to be able to meet up at last: what is also spooky is comparing our list of designs-in-progress.  Perhaps we should get together for some of the maiden and development flying work - I've already been dared to try and maiden mine without Scott being in attendance!
I must say that your Stumax looks very purposeful indeed but I'm not surprised that a dual-purpose pack will not be possible.  I'm still wedded (should that be welded?!) to my low-weight system, but that might all change after my 4s maiden... not that I've coughed-up for any flight-packs as yet.  Where did you get the Turnigy packs from Pete? 
Paul W.

I'm up for a mutual support maiden flying day if possible..................you can help me pick up the bits! 
 
I was pointed towards Hobby King's German warehouse as a potential source for packs for the Viggen, noticed the 3300 6S for $53 and thought they were worth a look. 
Have been doing some more of next winter's building:
 

That Viggen is a nice model, what a waste!   

Thanks for that Pete.  We will have to try and hook up for a session as you say.
The Viggen will be a great project - especially fitted with that StuMax - quality kit!
Paul W.

That Viggen is a nice model, what a waste! 

I'll happily accept a gift of one of your P80s to go in it instead 
Joking aside I'm not sure if I'll be able to make the JMA AGM now, I'll give you a call on Wednesday after work.
 

Thanks for that Pete.  We will have to try and hook up for a session as you say.
The Viggen will be a great project - especially fitted with that StuMax - quality kit!
Paul W.

Woodspring wings might be a good (realistic) target to aim for.  I should be back on either the 1154 or the Vulcan by then 

Dizz - this model is far too nice for edf! stick a P20 in it and be done with it! 

New P100 for the Viggen, and you'll be well sorted! Come across to the dark side mate! You know you want to! 

Mr Dizz sir...you do nice work !

 

Dizz - that 1960s RAF scheme (eg early Hunter or Harrier GR1a) is the sort of thing I'm thinking of using for my Squall - what are the actual colours? I've struggled to discover what the underside colour (a very pale blue/cream IIRC) would be in Humborl/Tamiya. I have the original Gr1/1a paint scheme drawings, but the colour references aren't even it DTD-speak; they refer to Hawker stock numbers

 

PDR

Dizz - this model is far too nice for edf! stick a P20 in it and be done with it! 

New P100 for the Viggen, and you'll be well sorted! Come across to the dark side mate! You know you want to! 

You are right on the P20, econ it would drop straight into a Mk2 version.  And the Viggen too, all I need is a spare 4 grand! 

Mr Dizz sir...you do nice work !

Thanks 

Dizz - that 1960s RAF scheme (eg early Hunter or Harrier GR1a) is the sort of thing I'm thinking of using for my Squall - what are the actual colours? I've struggled to discover what the underside colour (a very pale blue/cream IIRC) would be in Humborl/Tamiya. I have the original Gr1/1a paint scheme drawings, but the colour references aren't even it DTD-speak; they refer to Hawker stock numbers

 

PDR

I have been using Humbrol matt enamels for a while now airbrushed on.  To get the colours I check what paints are required to complete a suitable Airfix kit:

http://www.airfix.com/airfix-products/aircraft/military-aircraft/1951present/a11002-hawker-siddeley-sea-vixen-faw2-a11002/

For the 1121 I used M30, S164 and S166.
HTH

Pete

PS
Quick turn around on the Lipos and the 3300mAh 30C packs arrived today
I should have enough time on get some testing done on Sunday. 
Will update my spreadsheet and post on here then.

Pete
 

I never did get around to doing a proper test on the 3300 30C packs, but yesterday some 3000mAh 40C packs arrived, enthusiasm has been restored.  P1121 installed tests will happen very soon..............................honest! 


The new packs came with 5.5mm connectors fitted, but I'm different and put the male plug on the +ve side of the battery so had to swap the connectors over.  I wasn't very impressed with how the wires had been fitted though - a good shiny joint but only 2 or 3mm of the wire actually soldered to the plug.  I bared a few mm more of wire and soldered them pushed right up into the opening.



Was having a clear-out this afternoon and found this 4 year-old wing..................anyone guess what it is for?  I might have found a second fill-in project whilst I wait for the Viggen ESC replacement and release of the Buccaneer 

anyone guess what it is for?

me, me, me, me, me - you're a tease Dzz!

Garry

It even looks like the right wing section as well. They fly very nicely when built and much to my surprise will actually glide rather better than one might imagine. Mine doesn't have shock cones as I wanted the airflow to be a good as possible but with a 82.5% FSA outlet design and twin 55mm fans I probably could have squeezed them into the approx 54" of fuselage length.

me, me, me, me, me - you're a tease Dzz!

Garry

That made me smile, but I'm afraid your guess not allowed Gary....................because we talked about it on Saturday 


I have 4 spare 70mm EDFs complete with motors here waiting for homes, but they are all different so no twins.  I need to have a think on which fan is ear-marked for which winter project.

It even looks like the right wing section as well. They fly very nicely when built and much to my surprise will actually glide rather better than one might imagine. Mine doesn't have shock cones as I wanted the airflow to be a good as possible but with a 82.5% FSA outlet design and twin 55mm fans I probably could have squeezed them into the approx 54" of fuselage length.

This one was going to be a single 70mm fan, but if I do decide to do it I'll start again and probably make it a little larger - easy with CAD and access to a CNC machine.

This one was going to be a single 70mm fan, but if I do decide to do it I'll start again and probably make it a little larger - easy with CAD and access to a CNC machine.

What wingspan is the original wing in your photo 24-25" by any chance?

Spot-on................24 1/2"

Got to be TSR2 no?

Got to be TSR2 no?

Correct Jamie 
 
 
 

So that would go well with a couple of GWS 55mm with 5000kV motors at about 1200grams with about that amount of 1100-1200 thrust from a 3s 45C 4500 mAh with 40 or 50A ESCs..

One of my options was for 2 x Phase 3 56mm fans with Don's Wicked 5400kV motors, but I used them in a GWS A10 and that didn't last long.  Haven't been able to find the fans for ages now - lost in the move somewhere.

One of my options was for 2 x Phase 3 56mm fans with Don's Wicked 5400kV motors, but I used them in a GWS A10 and that didn't last long.  Haven't been able to find the fans for ages now - lost in the move somewhere.

Aaah that's funny you should say that my first EDF was a GWS A10 with 55mm fans and brushed motors it flew OK witha 3s Lipo but the motors didn't like it much so I swapped the 55mm for 50mm wemo clones stuck the 55mm in my TSR2 which was very light then with some 4000 kV motors which weren't really man enough but it had about 700 grams of thrust with an all up weight of 800 grams. I then folded the wings and managed to get down with no damage to the fuselage. Then I went a bit mad and beefed up the structure of the wing and stuck in the 5000kV motors and it went nicely at 1200 grams and about that in thrust.
Meanwhile my heresy of inflicting brushless motors on 3s with the wemo clones worked amazingly well in the A10 with the CG moved back a good way from the manufacturers recommended. on 35mhz it was rather a glitchy beast too much noise from the motors. Used to look great coming in over the house to land in the garden. The fuselage snapped pretty regularly across the back of the wing mount, until I beefed that up a lot, as the motors wore the noise and glitching got worse and on its last flight it chose vertical dive mode with full power into the ground from about 60 feet up. It now sports an EPP nose, and sits in a shed on its own for being a bad lot until I have some spare  brushless motors to throw in it if I can ever be bothered. It flew about 20 flights before the motors were getting tired and another 20 with some interesting moments and the final death plunge.

Same here.  I didn't bother with the u/c and used to bungee launch it off the ramp and used 10C 3S lipos too, but like you say the motors couldn't take it.  I have had afew EF-16s so therfore subsequently had a few EF-16 power trains become available.  I think it was 3 summers ago I swapped to them and gave the airframe a cosmetic make-over.  It went like stink and the wings assumed an alarming U shape in steep turns, but it held up for several weeks. Unfortunately the elevator control failed during the last launch and it just followed a ballistic curve to the scene of the crash.   
Big debris field, but the electrics all survived and I salvaged everything to use again.  Unfortunately I can't remember the really, really safe place I put them to await a new airframe   
 
Back to t he 1121..............the 6mm connectors didn't arrive today so no installed test figures yet but there I just remembered that I still haven't sorted out the play on the tailplane, so I'll crack on with that this evening and hopefully worry the neighbours with some 60,000rpm fan noise tomorrow instead