mcclayb

ideally, if you can cut out a piece of paper to match an inlet, then take trace it on a piece of standard paper (8.5 x 11), I should be able to calculate the surface area based on that. Otherwise simple length and height measurements should suffice. Thanks so much.

Bob_B

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About 10 years ago a flash was converted to EDF using a DS77 fan. It flew at one of the first Jet Jams in Muncie.

mcclayb

That’s good to hear — just looking to go bigger on the fan! DS 130, perhaps 😆

acw

My Feedback: (1)

I have a few composite EDF (Bandit EDF and EVO) and own an Ultra Flash. Honestly I have a hard time to believe you could electrify it in a way which would be satisfying. First, the air intakes are designed for a turbine and are very small compared to say a Bandit. But then you will need a full duct with the edf and won't have any room for some serious batteries unless you go for low on capacity. Finally the weight is going to be an issue. The UF is built to be very robust but as a result isn't super light. With batteries and motor you will probably be around 11/12kg. Mine is 10.4kg completely dry with a Jetcat 130. Again, electrifying it is probably possible but I doubt this will lead to a satisfying result, either from a performance perspective or time of flight.

I hope you prove me wrong. This is an amazing jet that would be so cool as an EDF.... Please PM me if you need any further measurements.

Arnaud

essyou35

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There is a huge thread about these brakes not working.
JP hobby elec brake question

NO idea what Dave's issue is but this forum is still full of the same old dumb asses from years before. no wonder its dead around here.

Ill get the measurements for the intake instead of telling people why and EDF wont work like I seem to know everything.

essyou35

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Hope this helps. Good luck on your conversion!

Bob_B

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The are two things to consider, Inlet area and Exhaust area. The DS77 now DS82 flew the model well. It was not super fast and the flight time was 3-4 minutes.
regarding the inlet area measurement, that is taken from center of the inlet radius to be accurate not the outside edge.

mcclayb

Thank you!

mcclayb

Thanks so much -- very kind of you to take the high-res pictures and the time to do it all. Much appreciated.

essyou35

My Feedback: (11)

https://photos.app.goo.gl/oMZqp3zprJbpjKTm8
my brake issue

essyou35

My Feedback: (11)

I've done everything I can to fix the brakes.
I'm going to just buy electron wheels and brakes and fit them to the jp struts.

My take off roll is long so I'm considering 70mm tires instead of 75mm.

jp brakes do not work well even with xicoy controllers. The metal disk is chinese metal and the rubber the disk rubs against doesn't grip it well. The magnet doesn't pull it stri gn enough either due to low iron content. I got some better grip by coating it with rubber cement. But that is a solution that won't last. It doesn't affect the wheel movement much when brakes are not on.

Viper1GJ

My Feedback: (20)

Please post photos on how you will do this. I have thought of doing it but it doesn't look easy. Thanks.

camss69

My Feedback: (46)

Well, good news and bad..

Had a very successful maiden yesterday, Dave was right on about the CG even though I was very apprehensive about it. @235 I was still nose heavy on takeoff.

Had 3 successful flights but the 3rd landing bounced the landing and unfortunately did some damage to the left elevator causing a partial delamination of the hinge.

What’s the best way to fix the delamination of the hinge? I’m hearing finishing resin but I’m concerned with getting pressure on it while it drys, it not running everywhere and getting into the hinge line. The attached pic you can’t really see it, the delamination is just to the right of the blue line I drew. I’ve also heard thick CA? My own solution was cover the hinge line with Vaseline and then using fresh thin ca while applying pressure from the outside?

Although I’m nose heavy, while on the ground, the plane is VERY light on the nose gear, after landing and burning fuel while flying, taxing back the nose gear is bouncing. This is with the Electron gear which I know is different from the factory gear but this seems really odd. The wheels are in the wheel wells obviously and go down 90 degrees or whatever so shouldn’t they be in the same place when extended and retracted as the factory gear? I’m not understanding exactly what’s going on here.

What about putting some blocks under the front of the gear to try to angle it further back while it’s extended? It’s about the only thing I can think of that would maybe** help?

camss69

My Feedback: (46)

Forgot to mention… the Swiwin 170 is very easy to manage in this plane, I was really expecting to have issues with residual thrust as well as flying around at 1/4 throttle but that was not the case at all really. The plane flys very nice and precise and I’m looking forward to getting a lot more flying time on it.

camss69

My Feedback: (46)

I think the issue you may run into is that the axles need to be exactly the right length because they use c-clips to retain them. The Electron gear also uses a set screw from the bottom of the gear leg into the axle. I think it might be difficult to get the proper axle length so you have the right spacing for the brake disc if that makes sense. If the strut is wider than the factory Electron strut you might be able to machine it down so it fits exactly right, if it’s narrower you might be able to use some washers for proper spacing. If Electron was smart they would create some sort of retrofit kit so people could use their wheels/brakes on JP gear, they would sell a MILLON of those I bet.

essyou35

My Feedback: (11)

Hey cams, I feel for you. I have a brand new jet Im banging on, drilling, wacking to get the stripped set screws out of. Then Im not flying due to flaw in the brakes.
IMO I would buy a new elevator if you can, they are pretty cheap. Otherwise your suggestions would probably be fine.
The JP gear is also light on the nose. But not as bad as you state with electron

If I were to have electrons I would increase the rake angle of the rear gear. This may require you to grind out some material in the wheel well. The gear are too close to the CG.

In terms of the brakes, if I understand what you are saying, as long as the axle is long enough, I can cut it or I can let it stick out the back of the strut? JP is the same way being a cheap chinese junk copy, the axle needs to be set correctly to ensure the axle sticks out the rim enough to get the clip on without having too much play.

CARF needs to address the gear issues. Unfortunately JP hobby has proliferated the hobby and it is damn near ruined IMO. Junk everywhere.

essyou35

My Feedback: (11)

BTW another option on the gear other just raking would be to physically move them back. lots of grinding and filling to do it but thats where we are at with this jet and gear combo.

scoeroo

My Feedback: (9)

Darrel at Sierra Retracts has custom axles that can be cut & fitted , they worked great with the electron gear installed in my u/flash

Dave Wilshere

Finishing resin is the best option. Run grease along the hinge so the epoxy does not get into it. Because what you have done is cracked the foam, there is nothing to fill. So thin glue is what you need. Warm the resin a little, with the elevator folded up as much as you can and the tailplane leading edge down, brush in a few loads of resin. You can close it up to check when it’s full (bubbles out) before taping the elevator fully down position and leaving over night to set.

Put a skid under the centre chine to protect the elevator horns.

Flew my Evo today in a cross wind, still brakes straight. A friend who has some of your issues collected an Electron E brake control unit to try on his UF Evo/JP set up.

essyou35

My Feedback: (11)

I tried a xicoy brake controller on a 3s life. With the and my glue mod they work ok. I'm going to get electron wheels. The wheels did lock.

Btw other than the brake issue the flash is the best jet I've ever owned. It flies amazing.

The take off roll is long but in not using flaps. Going to set that up next.

camss69

My Feedback: (46)

Thank you Dave, that’s what I’ll do.

Dave Wilshere

My guess is you are firewalling the throttle pushing the nose down. I open the throttle quite progressively, I rotate 150’ every time, the UF is not a ‘jumper’ it will smoothly rotate…or put a 1/4” packer under the nose retract unit.
3/4” TO flap with a little more than 1/32” down elevator set from your clean position.

essyou35

My Feedback: (11)

I ordered the eletron wheels. 75mm 11mm width and 6mm axel. Should be an exact fit assume axle long enough.

The TO flaps did help but IM having a lot of issue keep this jet on the runway on takeoff. Its all over the darn place coupled with the long takeoff not a good combo. Im guessing the mod I did to the rubber may be causing some unequal drag.
I do plan to increase the AOA that should help as well.

This jet knife edges so nice with nearly no coupling.

essyou35

My Feedback: (11)

For anyone who has issues with jp brakes not working correctly, the reason is that this type of brake system requires a strong magnet coupled with precise machining, something JP cannot do. Further they cant make a controller to save their lives. The retracts themselves though seem barable.

I manage to adapt the 75mm electron wheels and brakes to my JP struts. I mis measured, I though the strut was 11mm it is actually 13.

The way the electron keeps the wheel from rotating is by using some 2.5mm screws and the heads of those screws bump up against the strut. Since I needed 13mm and not 11, I simply took some 2.5mm screws and cut the heads off and am using the screw bodies as anti rotation pins. The JP axles are not long enough as the electron magnets are like twice as thick. Some cheap SS 6mm barstock from amazon and I had a new axle. Electron offers axles that are 6mm and 38mm long, I think that those would work perfect but for some reason I though they came with the wheels. The use a clivis pin design so no need for an e clip which is much much better IMO. I plan to order those with my 55mm wheels for my mini avanti.



I dont have any machining stuff just a dremel so excuse the less than stellar looks. Im also using xicoy brake controller I highly recommend it.

essyou35

My Feedback: (11)

BTW one thing you could do is sand one of the stock 2.5mm bolt head flat, that would also work. IMO the tires will skid before the screws give out.