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

[Steven S]

Posted by Steve Balaam on 02/12/2018 14:12:06:

The TN Sabre is next on my building list. There has been a lot of discussion about getting sufficient air in to the fan,

I'm going to use Naca ducts on mine, what are the tell tale signs on the ground that the edf is not getting sufficient air and is being choked ?

I picked up an "Aeroplane Illistrated" book on the F-86 and found apicture of a F-86C with NACA ducts.

It may make mounting the elevator servos a bit more fiddley.

Edited By Steven Shaw on 05/12/2018 14:49:02

[Erfolg]

Apparently it was a one off, given a temp designation of F86C before given a permanent designation of YF-93A. The standard cheat holes, that many models use, that is a louver arrangement underneath, just in-front of the fan seem to work well. I guess the louver arrangement is to minimise the risk of ingesting debris when landing.

There is potentially the option of doing a F100, or FY107A using pretty much the same wing and modified body. The only reason i have mentioned the YF 107A is that having a dorsal intake, making it bigger and being short could help the fan to breath without, the deviations being blindingly obvious. Plus the inlet is well away from ground damage.

[Steven S]

Yes - I've been looking into that also.  Just dont want to weaken the wing joint too much.

Edited By Steven Shaw on 05/12/2018 16:40:53

[ken anderson.]

here's a couple of photo's of mine,the nose and the view from above to show the radio gear in the floor of the cockpit.the model seems to have a fair size hole at the front,plus the large "slec" intakes on the side,in front of the fan...….

ken anderson....ne..1.....Fan dept.

[Erfolg]

Ken

It will be interesting to hear how it goes.

I quite agree that the intake is quite large. My only doubt and very real interest does all the gubbins in the duct make much difference, although the additional side intakes i guess will make up for any duct losses (that are material).

It is duct losses that could make a YF107a attractive, although again the duct shape will not be ideal. The Lipo etc. can be arranged to be in the front of the body. There is another downside in that the cross sectional area is greater due to the body being underneath.

I have been attracted to a Heinkel 162 just due to the ideal duct. But every time I look at drawing the body it seems enormous.

It is possibly the performance of the fan units that you guys use that will point the way for those of us watching.

[Tony Nijhuis]

Evening Guys,

I don't often get on to the forum and even less so due to putting a stop to building and designing due to health reason......

Firstly Ken....14 amps draw from the FMS 50mm fan is low so there is something wrong......25-30amps or more should be expected according to the data sheets. Suggest the ESC maybe at fault....for info, i used a cheap 30amp quadcopter ESC with the AEO 50mm fans as it a simple switch on a go....no programming to screw you up.....current draw was around 25amps. Secondly, strangling or restricting the fan will not drop the current draw so it is nothing to do with restriction!!!!!

Regarding other comments concerning flying.. i think the photos speak for themselves taken by the editor... I'll say no more!!!....

What I will say and should be obvious is that if you put a more powerful fan in the model and keep the same air intake cheat hole you wont necessary get any more thrust. The fan will simply not be able to breath!!!. SO increase the cheat hole opening or you'll be wasting energy!!!!!.....A more powerful fan will need a larger battery....(possible a 2200) which will add to weight....QED more weight but no appreciable increase in thrust (if you don't increase the cheat holes).....results in poor performance.....It is a fine balance between AUW-and thrust ....

I have just bought some of these FMS 50mm fans so hope to try them out in the Concord soon, as they do look promising

[Ian Moody]

The photo's look great Tony and they are great that they are taken by the editor but I wouldn't mind a video of them flying so I can see how well they fly to give myself and others inspiration to persevere with ours. Thanks

[ken anderson.]

hello Tony,sorry to hear of your health problems, hope you are on the mend. You may have mi-read my many posts,the fan i'm using is the HK Dr madthrust(not the FMS unit)) 50mm edf,3s/4800kv/max 450g thrust,max amps 18.i've had a go with a brand new lipo and am now showing 16 amps/170 watts...the model appears to have plenty of static umph...so watch this space for feedback on the maiden...… take care tony.

ken anderson...ne...1...madthrust dept.

[Wilco Wingco]

How about a British jet??.

[Ray Wood 4]

Hi Tony,

Sorry to hear building on hold 😕 shame we are not doing the Savoy this year ! What happened to Red October ?

Regards Ray

[Tony Nijhuis]

Im sure David Ashby took some video on his phone so maybe he can pop it on somewhere.....or of course post your own....there are a fare few flying out there now....

Ken, these HK Dr MT fans are from Lander so you can check their web site as it will give more technical info.....These fans are nice units and suggest they develop the same thrust at lower current than the AEO which are more power hungry (24amp at 450g).....so the Dr MT should be ok and you could use a slightly smaller lipo as the current draw is less.......the Dr MT is an ounce heavier though so it is a balancing act.

Depending on how I feel, i may produce another two modern jet around this size later this year.

Hi Ray, good to hear from you....had a bit of a falling out with the new editor of MB so gave Red October to SLEC to add their fleet of boat kits they do....

Some good new for those who are not up to building , the MiG-15 and Sabre will soon be produced as an ARTF kit !!!!.....Traditionally built to match the original plan design, covered in film and fitted with fan unit.....no more detail at this stage.....

[Piers Bowlan]

Posted by Wilco Wingco on 13/12/2018 12:07:45:

How about a British jet??.

AN EE Lightning would be popular (one fan not two please!) and a Hawker Hunter would go down well too.

Sorry to hear of your health issues Tony. Get well soon.

[Steven S]

I’ve finished the main fuselage except for cutting out the hatch. I’ve also finished the tail feathers. I had to make one of the elevators over again after one of the slits for the hinges broke through. I have a hard time putting hinges into 1/8^th. I’ve also shaped the main wing and am fitting hinges to it now.

I followed the plans for everything and the only minor discrepancy I found so far was the 2 holes in Former 8 aren’t required when inserting the control cables. I’m very happy with the plans and will make the MIG also.

[Jack Petrie]

Hi all,

Here is a few pictures of my build. Haven’t had much luck flying yet, I’m wondering if I need a bungee as from hand launching I can’t seem to get enough momentum for it to get going.

[ken anderson.]

hello jack, nice model there...….mine(the sabre) is ready,i'm going to pick a day with a slight wind...to help me defy gravity......i'll let you know the result..dont know if you've read Ian Moodys comments about his mig…… looking at your photos.....look's like ...not much of a draught will get through the front fuz to the fan.....

 

ken anderson...ne..1...results dept.

Edited By ken anderson. on 20/12/2018 18:59:04

[Jack Petrie]

Hi Ken, good luck with your first flight! I actually do have the air scoops from SLEC under the wings which you can’t see in the picture. Maybe I picked a bad day for weather or just didn’t give it a hard enough throw! Going to try again on my next day off. Jack

[Ian Moody]

Good luck Jack. Keep us posted and if possible get someone to film it in flight.

[Tony Nijhuis]

I can't see any cheat air intake holes in the sides of the fuselage? .....it wont work unless you do.....the larger the holes are the more thrust the fan will give

[Steven S]

Very nice looking build, what EDF unit did you use?

[Chris Walby]

Been watching with interest, only comment is that I have an edf and it has large inlet + cheat holes top and bottom of the fuz (quite large underside ones). I think the would have fitted cheat holes to the sides if they could have found room!

PS seems a bit counter intuitive, but flying when there is a good breeze really does help the hand launch part. I have a model you have to launch downwards so it gets the air speed to gain control.

[Nigel R]

Mig looks great, Jack.

Anyone tried the WeMoTec unit?

[Jack Petrie]

Tony- I have cut the air intake holes in the sides of the fuse under the wings and used the air scoops you recommended, I did it later on in the build near the end of covering and you can’t see in the last pictures.

Thanks Steven, I used the 10 blade cyclone power red unit.

Jack

[Erfolg]

I have noted a number of suggestions for future designs/builds.

The problem with many jet aircraft that their wing area is quite small relative to the body cross section.

Although I can imagine that many UK modelers this aircraft is not one of their favorites, The Phantom 2 has a big wing, very large air intakes. All relative to cross sectional area. In the case of the phantom, they could be enlarged quite a bit without becoming very noticeable, also the duct length id short. Rather than two fans, one central would probably perform more efficiently. Another aircraft along the same lines was the Douglass Sky hawk, although the intakes were proportionally smaller. Both have the advantage in that the Lipo would be in the body, not partially obstructing the duct.

[Tony Nijhuis]

For clarity, both the mig and sabre have an AUW of 15oz with a wing area of approx 1 sq foot....so these little jets only have a wing loading of 15oz/sq' which is very low for any model so hand launch is very easy.....remember that the old hand launch 42" Cambrian WW2 fun fighters were approx 28oz/sq' !!!

[Marc ROCHE]

Hi all,

I started the Mig this afternoon. It has a RCLanders 10 blades motors 3S 40000KV, 30A Protronik controller, 3 Hitec HS35HD servos, Xpower receiver. Mass total 293gr. A 3D print thrust tube (thx for my boss Michel) 42mm exit diameter mass 25gr.