Catastrophic air frame failure
 

Lost my Hot Spot, bottom section behind main landing gear blow off at about 150+ at 30 ft. hight. Has this happen to anyone else, attach picture shows the piece that blow off, any info will be appreciated. xxspeed

RE: Catastrophic air frame failure
 

Yes, this has happened previously to Hotspots & Roos. Typically (from what I have read here on R/C U, never happened to me) the lower skin has delaminated and airflow in through the wheel well openings has provided the force to tear the skin off.

What happened after the bottom delaminated? Did it peel all of the way off? Did it hang on and the drag caused the crash? How/why did it go in?

Sorry to see this.

RE: Catastrophic air frame failure
 

Thanks for the reply, it peel off with no warning and separated from plane, Hot Spot noised down up elevator had on effect, hit about 200 ft from filght line. My though now last year i had a fuel leak on the side that failed maybe that caused the glue to weaken?

RE: Catastrophic air frame failure
 

One of the flyers down here in Florida had this happen also. Made no noise just blew apart in the air we thought it hit a bird or something looked just like what happened to you nose was gone and peeled top off.

RE: Catastrophic air frame failure
 

I suspect that your fuel leak could possibly have weakened the plywood on the formers that are glued to the bottom skin. But the glue (I think they used epoxy with a white filler) should not really be affected by fuel. Can you tell if a bit of former is still attached where the bond failed? Or does it look like the epoxy just came off of the bottom sheet?

From the other examples of this that I have read here, it seems like many of the past failures were simply a case of not enough glue used or not an adequate bond from the manufacturer.

RE: Catastrophic air frame failure
 

Hi xxspeed::)

Condolences for your Hotspot.

I sell my Hotspot, If you want it? :D:D:D

ONLY 1,000.00 EUR = 1,275.25 USD


Now I am painting for that look perfect (you can schosse paint scheme). Complete,, withow Turbine, pump, valves and receiver.


Best Regards from Spain.;)


.

RE: Catastrophic air frame failure
 

Sorry for your crash...

Yes, the HS has this problem, if built in the original way... after some flights enduring the stress forces and landings, the fuselage starts to de-laminate from the formers and starts to get flimsy. The solution is to glue CF strips along all the formers and adding a 1 inch CF strip on the fuselage
this coupled with some details and twin wing tubes make possible full power dives on a 34 lbs turbine up to 400 mph.

It would be good to current HS flyers reading this thread to remember to check their fuselages to
avoid what happened to yours.

Enrique

RE: Catastrophic air frame failure
 

Yep, on my Hotspot the skin behind the wheel well formers were completely de-laminated, I don't know how long for but canceled my next flight until I fixed it......it was a disaster waiting to happen.

Sorry about you loss, they are awesome jets.

Goose

RE: Catastrophic air frame failure
 

Many HS have this problem, the cause is really air entering through the wheel wells, building up pressure in the fuselage, litterally "blowing" the glue joint apart. This is then immediately followed by delamination. You can either add wheel wells and doors, or just use a very simple fix: cut slots into the bottom aft of the fuse, below the turbine. This will allow the air entering through the wells to escape, thus unloading the joints. High speed flying is apparently no longer a problem. I'm putting a HotSpot together at the moment and will be using that method, it's been suggested by various different people i've talked to here in Germany.

Regards
Hank

CMjets: the colors on your t-bird scheme are way off......especially the blue :-)

RE: Catastrophic air frame failure
 

Wokeman, looks like the epoxy came off the bottom sheet, there on pieces of formers at all and the tears are clean that is it just happen. Pic of both sides. Thanks for the reply xxspeed

RE: Catastrophic air frame failure
 

Minflyer, great tip Ill past it on to other Hot Spot flyer i know, the vent hole.

RE: Catastrophic air frame failure
 

If the epoxy has just come off of the bottom sheet, that can be facilitated by many things. Like if the guy assembling the fuselage was just eating greasy fried chicken, did not wash his hands, and gets grease on the bottom sheeting where the former is to be glued - disaster. I doubt they prep the bottom surface by roughening it up like you & I would if we were gluing to it.

RE: Catastrophic air frame failure
 

Hi Guys

This problem was observed mostly on the earlier hotpsots. The glue joint on the trailing edge of the fusalage is a blind joint (thats what I was tols by one of its original test pilots). Later ones have this joint beefed up. As miniflyer correctly stated above it was caused by air entering the rear wheel wells and creating possitive presure within the fusalage. The rectification was, as again correctly stated by miniflyer, to drill holes or slots along the bottom trailing edge of the fusalage or use gear doors.

Regards

Paul

RE: Catastrophic air frame failure
 

xxspeed I have one built with all gear doors minus paint. If your interested I can send you pictures. I just don't have time to finish it but it's very fine quality work I have done on it. Let me know and I can make you a great deal. I have posted some pictures here on RCU just do a search for user ledd4u.

RE: Catastrophic air frame failure
 

Bryce had a Hot Spot that exploded the same way in the air.