New EDF Mini Jets- Sabre & MiG15 RCM&E 2018 Special

[Christopher Long 1]

My Sabre had its maiden on Monday, built using the originally specified AEO unit, and as designed by Tony, it flew like a dream. A fellow club member who has a lot of experience with EDF did the first flight and trimmed it and he said it flew really well with plenty of power in reserve and loved it!
Really pleased with it, but I did have to put in a lot of work on the supplied kit as the wood sizes supplied differed from the plan and the cut slots in the plywood formers! For instance the fuselage square stringers are specified as 4.5mm on the plan and the formers are cut to that size, but the wood supplied was I guess meant to be 3/16th sq (4.76 mm) but was 5mm square (nearly 15% bigger than specified)! The same could be said of the specified 4.5mm sheet which was again 5mm thick. I know a little variation in size is to be expected, but this was the worst I have experienced from a supplied kit. At most I would expect a 5-6% variation especially when it needs to fit into accurate pre-cut formers.

For the pilot I used Real Model Pilots who do a military version which is just about right at 1/16th scale (the Sabre model is about 1/17th).

Despite the problems I am looking forward to building another EDF (this was my first) from Tony.

[Tony Nijhuis]

Glad it flew ok Christopher with the AEO set up......The new generation of 11 bladed 50mm fans now available give so much better performance.....still you can try them in your new project!

Woody, The Lightning is still on the building board so no picts yet

[Mark Elen]

Thanks for the info Gents.

I decided to buy a couple of pilots from RMP, as I’m getting stocked up for the Phantom at the same time. It’s one of my favourites. Thanks for the offer Tim👍

Heres my progress on the Sabre:

It’s a great ‘quick build’ project.

Cheers

Mark

[Marc ROCHE]

I replaced the RcLanders EDF with a bangood FMS.
Effectively this one pushes well, in 3S the Mig keeps on the spot vertically.
Finally, his replacement was not too difficult.

First Mig flight this morning despite the wind. Unfortunately I could not make video.
First flight, the plane was very quick at the fins. Attenuation of the deflections to 60% for the second flight. I will have to retouch the mechanical deflections and the position of the Lipo for the CG.
He is magnificent in flight with his swept wing, and the landing is easy despite the 500gr of mine.

Well done Tony!

[Tony Nijhuis]

Glad you got there in the end Marc.....the little FMS fans don't disappoint

[Marc ROCHE]

I replace the 3D printing thrust tube by Xray film. I won 20gr in the queue.

(With the heat wave the PLA melted into the car!)

 

https://www.youtube.com/watch?v=WO1K8Pi3c4w&list=PLVwZ7Xc-U3ZKc_wUZdbNgKdGmAsg_ywCL&index=2&t=0s

 

I will make a variant of the mig and cut out the elements to make Mystere IVA.

Edited By Marc ROCHE on 07/07/2019 15:26:30

[David Clark 18]

This is my first ever posting. I've been looking at these two jets with keen interest and I can't wait for the phantom to be available. I intend to build the Mig 15 first as a practice so that the phantom hopefully will go without a hitch.

The club's flying site is a disused runway with cropped fields either side. Has anyone put landing gear onto one of these planes and If so how have you done it, or is there a good way of protecting the underside from the very abrasive runway.

As you can probably tell I am a relative newby and would appreciate any help you could give.

Edited By David Clark 18 on 08/07/2019 23:18:12

Edited By David Clark 18 on 08/07/2019 23:19:03

Edited By David Clark 18 on 08/07/2019 23:20:21

[Stephen Jones]

Posted by Marc ROCHE on 07/07/2019 15:14:18:

I replace the 3D printing thrust tube by Xray film. I won 20gr in the queue.

(With the heat wave the PLA melted into the car!)

https://www.youtube.com/watch?v=WO1K8Pi3c4w&list=PLVwZ7Xc-U3ZKc_wUZdbNgKdGmAsg_ywCL&index=2&t=0s

I will make a variant of the mig and cut out the elements to make Mystere IVA.

Edited By Marc ROCHE on 07/07/2019 15:26:30

It sounds as though it has a real jet in their .

flies as well as it sounds.

Nice one.

Steve

[Marc ROCHE]

I replaced the video, I m not too smart with my post youtube.

https://youtu.be/tZPAQ0TMzOo

 

Edited By Marc ROCHE on 09/07/2019 08:16:46

Edited By Marc ROCHE on 09/07/2019 08:17:09

[Marc ROCHE]

Posted by David Clark 18 on 08/07/2019 23:16:04:

This is my first ever posting. I've been looking at these two jets with keen interest and I can't wait for the phantom to be available. I intend to build the Mig 15 first as a practice so that the phantom hopefully will go without a hitch.

The club's flying site is a disused runway with cropped fields either side. Has anyone put landing gear onto one of these planes and If so how have you done it, or is there a good way of protecting the underside from the very abrasive runway.

As you can probably tell I am a relative newby and would appreciate any help you could give.

Edited By David Clark 18 on 08/07/2019 23:18:12

Edited By David Clark 18 on 08/07/2019 23:19:03

Edited By David Clark 18 on 08/07/2019 23:20:21

Can be try aluminium tape under the fuse. This is the solution I had considered before removing it, there's no sweet green grass at home.

Otherwise 2 rails in square balsa glued under the fuse, witch will be replaced by cutting and sanding if they used, a bit like the keel that is glued under the f86 sabre

[Nigel R]

I would probably go for a couple of skids on something this size.

If you use a central balsa rail, try curving the underside a little and fixing a length of steel wire to it. I'd put it over the CG position with most of it in front of the CG.

A couple of very light tip skids would prevent it leaning over and scraping wingtips.

[David Clark 18]

Thanks. It's looking like skids are the way to go. Would you putskids on the wing tips as well?

Edited By David Clark 18 on 09/07/2019 12:30:10

Edited By David Clark 18 on 09/07/2019 16:26:38

[Daithi O Buitigh]

An alternatrive (I've used it on foamies) is fibreglass tape .

A couple of strips on the belly and each wingtip should work

[Steven S]

I used "Crystal Clear Gorilla Tape"

Gorilla Tape

[Colin Bernard]

Well my Sabre was finished and ready for its maiden - and failed miserably, getting effectively a 30' powered glide with its FMS 50mm fan.

During my testing I am getting nothing like the thrust others are reporting with their fans so looking for ideas!

Stats: AUW = 21oz

LiPo: Dynamic 2200 3S

At WOT I got 32A, 378W

Holding the Sabre over the kitchen scales I got a max of 460g (~16oz) thrust but that soon dropped to around 350g.

I tried the same using a brand new identical fan and still got the same - 470g.

Interested in any thoughts so I can get this bird flying as at the moment it is putting me off trying any other of Tonys mini jet projects.

BTW - safety tip. If you have to hold an EDF unit to test it, hold the shroud at the motor end. I held it at the other end and got a cut. When at speed the blades stretch and almost close the gap between tip and shroud. Although I was using a very light pressure to hold it was enough to close the gap so that the blade tip sliced through the shroud and the side of my thumb! An EDF test mount is now being designed!

 

Edited By Colin Bernard on 23/07/2019 15:56:36

[Alan Gorham_]

Tony's website listing for the Sabre quotes a 16oz AUW and minimum thrust requirement of 600g.

I would look to lighten the model if you can, but failing that I would be checking the timing setup of the ESC, checking the ESC endpoints are calibrated so that it is delivering full throttle at full stick and then maybe check the voltage of your Lipo with a wattmeter at full throttle. If your Lipo is tired or isn't a high enough C rating then it will struggle to deliver enough amps.

I'd also confirm that the duct and cheater inlets aren't obstructed.

[Tim C]

Not enough air to the fan, I got nearer 700gm on my kitchen scales in a raw open test, if the the motor is being starved of air, or the thrust tubes restrictive you will loose a lot of thrust, your amp draw looks about right.

[Colin Bernard]

Thanks for the quick replies - but already thought along these lines.

As to the AUW this is down to my using a 2200 rather than the 1500 Tony uses in his lighter version. Can't take any more wood out - sanding through in a couple of places as it is! And there is no paint on it other than the flashes. Having said that, the AUW does not affect the thrust.

ESC has been calibrated, and the LiPos were giving 12v or more on the wattmeter.

I thought about the 'C' rating and tried with an almost new 45C graphene. That simply gave me an extra 10g of thrust, as did testing it with the cockpit cover off in case not enough air was getting through.

Re duct obstruction, all wires have been hot glued out of the way so the only wires to be seen looking down the nose are those from the LiPo.

And don't forget I did test another fan in the open and got much the same, (hence the plastered thumb), so airflow is not an issue.

I'm sure you can understand my bewilderment here. I already use the FMS 70mm fans and they are superb but am starting to doubt these.

I do have the AEO fan, so I guess the next step is try an open test with that, but need to get it soldered up first.

[Alan Gorham_]

If your thrust was a constant value then upping your weight 5oz over the designers prototype will certainly help you to achieve a powered glide.

You just have some fantastic 3s Lipos if they are showing over 12V under full throttle load! I wish any of mine would do that.

I suspect the 12V you have read is the off load value which is pretty meaningless.

[Mark Elen]

Quick question..

Are you sure you have the 3s version of the fan/motor set and not the 4s one?

Specs from FMS:

Description:
Brand Name: FMS
Item Name: 50mm 11 blades Ducted Fan 
Motor: 2627 KV4500(4S)/ KV5400(3S) (Optional)
Weight: 75g

Cheers

Mark

Edited By Mark Elen on 23/07/2019 17:16:51

[Geoff Gardiner]

Just a thought - you have got the 3S version of the FMS fan and not the 4S version?

[Geoff Gardiner]

Mark beat me to it - whilst I was typing.

Edited By Geoff Gardiner on 23/07/2019 17:22:59

[Colin Bernard]

Cant check the fan in the model without chopping up the fuselage but it was certainly a 3S order!

The other fan is definately the 3S version.

As to the voltage, yes that was the off load voltage to stop someone wondering if tbey were fully charged or not. They were and showing 98%.

When running i focus on amps and watts. But i did note the voltage on running which started at 11.8V, dropping quite quickly to around 11.2V.

Edited for typos...

Edited By Colin Bernard on 23/07/2019 17:57:09

[Alan Gorham_]

I've looked up the 3s fan specs on the 4-max website and it quotes 32A and 358W, so your batteries seem healthy to me and your fan is up to spec.

[Piers Bowlan]

Posted by Colin Bernard on 23/07/2019 16:48:43:

Thanks for the quick replies - but already thought along these lines.

As to the AUW this is down to my using a 2200 rather than the 1500 Tony uses in his lighter version. Can't take any more wood out - sanding through in a couple of places as it is! And there is no paint on it other than the flashes. Having said that, the AUW does not affect the thrust.

'The AUW does not affect thrust' Whilst this is true the extra weight will require extra lift which can only be generated with a higher A of A (at launch) = more drag - requiring more thrust. Without that the model won't accelerate and with the thin wing section the model needs speed to fly well (in my view). I don't know the difference in weight but I think it might be worth trying a 1500mAh LiPo for comparison and see if it improves on the 30ft powered glide. Light models fly better!

You have built a cracking looking model Colin, I am sure you will get it sorted.

Update: I just had a look at the HK website and a 40C 3s 2200mAh LiPo weighs 205g whilst a similar 1500mAh weighs 129g, so a 76g saving. I suggest that weight is probably fairly critical with this type of model.

Edited By Piers Bowlan on 24/07/2019 07:11:06