Originally Posted by stanordave

I've had a "few"Funjet Ultras ( 5! ). On the last few, the controls horns seem to be breaking real easily. Had one break this AM when doing an engine run. My flying buddy had his break on the maiden when landing. Different design or just bad luck? Whatever, I'm cutting them out and putting in something else tonight...

It always helps to rough up the bottom of the plastic horn before bonding it in place with a good quality medium viscosity cyano, NOT foam safe!

Originally Posted by Piledriver

Had my own tragedy today. Third flight on my Funjet Ultra and the unreinforced elevon tore loose causing a wild spinning crash. Airframe is totally ruined but luckily all my electronics survived. Hit the ground at a low enough angle that the right wing took the brunt of it and the canopy popped off and battery, esc and receiver followed it across the soccer field.
I'm bummed. I assume this was a fluke or do the elevons need a reinforcement on the hinge line?
I've had several Funjets and never experienced anything like this.

yes, reinforce the hingeline, best is with crossweave fibertape, clean with alcohol beforem then put it on over and under, will never tear apart again..

Also the original plastic horns, I dont know why you are flying with these when over 4s lipo and 1000 watts, i always make my own horns. other then they can loose up in air, the bad parts are: the geometry and that thin linkage wire, not for high speed at all, it will flex...

put a stronger horn, thicker wire(and some good clevis), reinforce the hingelines, then it will be ok.

I like to rough up the elevon and horn with some sand paper,then glue in place,mine are hiding up good with large amounts of power going through my FJU.
Long grass can tend to be the culprit on the horns when landing also.

Howdy Gryphon... Rim was lettin me know bout the readings on the graph....thats what I did, was move the mouse down a bit as the spike lowered...Thanks!!!!...ordered some more props for static testing...

If I was you fellas having problems with the linkage tearin away from the elerons...I'd switch over to the top side...I have, and it stopped those Tragedies...Grass and ground strikes can weakin the systems when landing....on original installations...I think its just an accident waiting to happen with undersides control linkage when belly landing...and I also lock my elerons on with Tape..after several years of flying foamies of different Makes...I've Never had a Flap tear away...Never...Hope this info might might help..Billy

Originally Posted by Piledriver

Had my own tragedy today. Third flight on my Funjet Ultra and the unreinforced elevon tore loose causing a wild spinning crash. Airframe is totally ruined but luckily all my electronics survived. Hit the ground at a low enough angle that the right wing took the brunt of it and the canopy popped off and battery, esc and receiver followed it across the soccer field.
I'm bummed. I assume this was a fluke or do the elevons need a reinforcement on the hinge line?
I've had several Funjets and never experienced anything like this.

I am very sorry your FJU got destroyed. If there werent any individual(s) disputing the unreliability of the stock hinge line, we wouldnt go through this. Read the following links and the posts that follow for details.

http://www.rcgroups.com/forums/showp...postcount=1995
http://www.rcgroups.com/forums/showp...&postcount=645
http://www.rcgroups.com/forums/showp...postcount=2006
http://www.rcgroups.com/forums/showp...postcount=2011

I could go on and on and on ...........................

Originally Posted by Piledriver

Had my own tragedy today. Third flight on my Funjet Ultra and the unreinforced elevon tore loose causing a wild spinning crash. Airframe is totally ruined but luckily all my electronics survived. Hit the ground at a low enough angle that the right wing took the brunt of it and the canopy popped off and battery, esc and receiver followed it across the soccer field.
I'm bummed. I assume this was a fluke or do the elevons need a reinforcement on the hinge line?
I've had several Funjets and never experienced anything like this.

Originally Posted by Jurgen Heilig

The turbine powered Funjets exceed those speeds at every flight. Enough said.

Jürgen

Jurgen,
Its NOT enough said !!!!
I will say it again and again untill the moderators suspend me, the stock FJU hinge line needs help !!

I suppose you still think that each individual who has had this problem was at fault themselves, eh ?

So far, this is like the 36th FJU that has suffered a torn off elevon with a stock - un-re-enforced hinge line that I know of. Maybe you ought to reconsider your adamant stand Jurgen, you are keenly aware that this is happening more and more, arent you ?

78 flights on two Funjet Ultras - blenderm used on hinge line for peace of mind - No issues. Max speeds 146mph

I never had a failure with a Multiplex product on the hinge line before my Funjet Ultra the other day, they usually stood up to lots of abuse before requiring reinforcement. I've been out of the sport for awhile and didn't realize the Ultra was occasionally failing there, well I'll still buy a new kit and start over with some reliability improvements.
Mine was/ will be powered by an HET 2w-25, 4 cell 3300, 6x4 sport.
This definitely wasn't exceeding the envelope for this airframe so I'm still disappointed, but , if some slight reinforcement is all thats needed then I'm good with it.
My 3 flights were very good until......

I find it hard to believe they still include those thin pushrods as standard.

Originally Posted by Piledriver

I never had a failure with a Multiplex product on the hinge line before my Funjet Ultra the other day, they usually stood up to lots of abuse before requiring reinforcement. I've been out of the sport for awhile and didn't realize the Ultra was occasionally failing there, well I'll still buy a new kit and start over with some reliability improvements.
Mine was/ will be powered by an HET 2w-25, 4 cell 3300, 6x4 sport.
This definitely wasn't exceeding the envelope for this airframe so I'm still disappointed, but , if some slight reinforcement is all thats needed then I'm good with it.
My 3 flights were very good until......

Mine went down on my maiden flight.
All thats really needed is some help for that hinge.
Most Dudes are running 3m x-treme tape or 3m mailing and storage tape for the extra support that hinge line needs.

Installing aftermarket hinges like Robart or DuBro is allways a great idea, but most times, the tape is all thats necessary if you arent exceeding 160-170 mph.

Originally Posted by feefo

I find it hard to believe they still include those thin pushrods as standard.

Agreed Feefo,ditch them for some 2-56...

Originally Posted by rimripper

Agreed Feefo,ditch them for some 2-56...

Well we got stuffed with the metric system so 2mm is what I use normally as it's the easiest to get.

question,
I am thinking about cutting the vertical stabilizers of my funjet and replace it with 3mm carbon fiber sheet, then if I feel a little difference in performance, I can also shave the front (about 1 inch) from tip of the wings and reinforce it with a long sheet of 3mm carbon fiber, its gotta be about 2"x10"x3mm, perhaps this will reduce the drag and make it go a little faster,
any thoughts on that ?

Originally Posted by kayvannouri

question,
I am thinking about cutting the vertical stabilizers of my funjet and replace it with 3mm carbon fiber sheet, then if I feel a little difference in performance, I can also shave the front (about 1 inch) from tip of the wings and reinforce it with a long sheet of 3mm carbon fiber, its gotta be about 2"x10"x3mm, perhaps this will reduce the drag and make it go a little faster,
any thoughts on that ?

For a $100 frame I think it is already fine the way it is.

Maybe servos aren't 100% secure, or there is backlash in the gear trains, or there's slop in the pushrod 'Z' bend where it enters the servo arm. Any of these could cause flutter and thus fail an otherwise perfectly adequate hinge. Mishandling the airframe in transportation or unsympathetic storage could also stress the hinge line. These are all valid reasons for possible elevon failure.