Ultra Stupid Funjet!!!

[Gabe]

Jeez!

Sounds like you are running into the same issues I had with my Strykers before I switched to balsa emetine and glassed the bottom. I've read that laying an additional cf tube through the wings from the top side does wonders. Also, some guys laid flat cf spars on the elevons. However, at those speeds, I've also heard of stock Fun Jets blowing apart in mid air.

Just outta curiosity, what's the kv rating on the motor? I'm debating on tossing in my scorpion hk-3086-1600kv for a test.

[akent]

Aug 16, 2010 9:38:14 GMT -6 Gabe said:

Jeez!

Sounds like you are running into the same issues I had with my Strykers before I switched to balsa emetine and glassed the bottom. I've read that laying an additional cf tube through the wings from the top side does wonders. Also, some guys laid flat cf spars on the elevons. However, at those speeds, I've also heard of stock Fun Jets blowing apart in mid air.

Just outta curiosity, what's the kv rating on the motor? I'm debating on tossing in my scorpion hk-3086-1600kv for a test.

Interesting you said that about these blowing apart!
A fellow at the field knows someone that flies at the north field that built a fast Funjet, too. At that field, they have a radar unit with a display that they put out on the runway from time to time. You do a low pass and it shows the speed. That's cool. Anyway, that fellow was trying to get a speed reading when his blew up. They said it just disintegrated! He never did get a reading. My radar gun won't read these either. I think the front profile is too thin.

I think if the canopy on one of these blew off, the wind would probably catch inside the fuselage and cause it to explode. I think I'll put in a couple of magnets on the canopy. I can't see any other way for one to blow apart.

====

Gabe, the Typhoon motor is 1800kv. Your Scorpion would be fun to try! Be careful on the current, as it really goes up fast when you try different props.
Kent

[elkmaster01]

Kent,,,I see they are coming out with a Funjet Ultra this month. You know anything about it? Thats what I have my eye on. I have the Typhoon 1800KV motor also,,,were you running it on 6S. What size battery will fit in it? I have a 100A ESC too.

I think the Funjet Ultra is just a beefed up Funjet.

I'm either going to get the Funjet Ultra and use the motor/esc I have,,or just buy a stock Stryker.

Which would you do??

[Gabe]

The FJ ultra is supposedly rated for up to 130mph. It has denser foam - that's it. Honestly, as much as I like the FunJet, I think the Stryker flies better and is easier to glass and/or modify. I think it also glides in easier than the FJ.

Here's the major selling point on the Stryker, the fuse is only $19.99. The FJ has no replacement parts, you gotta buy a whole new kit when you nose dive.

I do enjoy the FJ as an intermediate fast plane until I rebuild the Darkside Stryker.

[akent]

Yes, the Ultra might be a denser foam, but from some of what I've read, it's just a different colored foam with the wing tanks removed.

I hope it's denser!

I am running 6s on mine. An 1800ma 40-50C 6s will fit, but I had to cut the canopy some to be able to move it far enough forward for the CG with this huge motor. The fuselage is untouched.

I have flown both the Stryker and the Funjet and I will agree with Gabe that they Stryker is better behaved at slow speeds. I think it will never stall! It will land at baby crawling speeds and it slows down quickly. The Funjet will stall if flown slow enough.

But I think the Funjet is more like it's on rails at high speeds.

The Funjet from my experiences is good for 110mph with a completely stock airframe.
At the point when my stupid one loses control is WAY faster than 110. But I don't know how much.

The Stryker airframe from my experiences is good for 80mph in completely stock form. After 90 or so, it starts to get weird.

I still have the beginnings of a dark side Stryker build!

I think though that a stupid fast Stryker and a stupid fast Funjet might pretty much end up needing the same beef once you start going stupid fast!
Kent

[Gabe]

So does anyone else have an issue landing their funjet? Mine comes in super hot, even on a long glide. The issue I have is that at a certain speed, about 10-15 mph, she just drops like a rock and hits the ground. There is really no floating to a gentle landing. He hits hard and fast.

I'm thinking it may be the 3600mah 4S battery I have in there. It's a little nose heavy but she flies straight as an arrow at full speed.

I'm starting to get some torque roll too. The foam on thr ailerons seems to be getting a little flimsy too - possibly from the high speeds. I'm thinking it's time for some upgrades on the ailerons and pushrods.

Also, I have absolutely no faith in the hatch latches. I've never flown without extreme tape holding the hatch on.

Any ideas on this - or comments?

[akent]

That's a huge battery, Gabe!
I'm flying an 1800ma 4s in my 110mph Funjet.

I would not doubt that all of that weight is causing yours to stall at a faster speed.

Mine takes a while to slow down, but I can land it at pretty much a walking speed. I come in from the last turn and glide as low as I can without touching down. Maybe 1-2 feet off the ground. It slows and I keep giving more and more up elevon until it greases in.
I did stall it a couple of times when I first flew it, but I have landing down pretty well now.

I land the really fast Funjet the same way, but it is a lot heavier, so it does come in hotter.
Kent

[19000rpm]

I'd agree with Kent that it's heavy, but that shouldn't cause it to stall at 10-15 unless the wing loading is off the charts. Maybe it's too nose heavy.

[Gabe]

Yeah, I'm thinking that's it 19K. I need it to be a little nose heavy due to the speed, but I think I was being over cautious and its simply just too nose heavy.

I moved the battery aft just a smidge and checked the CG - still nose heavy, but not as much. 3 runs at the park with a 100 yard field allowed me to glide in nice and gentle.

[19000rpm]

A little too much weight bias either way can cause a problem, but a little nose heavy is way better than tail heavy.

[akent]

Well, I have 6 flights on my U.S. Funjet now.
I flew it today after a three week non-flying haitus getting my daughter settled into College, going to a wedding at the southern north pole and finally I was able to fly today!

After the first two flights a few weeks back where there was little to no control after some really fast passes, I put some carbon along the trailing edge of the elevons, beefed up some the control linkeages and now it is controllable at speed!
Estimates still range around 140-150mph. It is way faster than the 110mph Funjet, still.

I also think the CG has some to do with handling as you found out Gabe. I put the CG right on the stock little button and it flew VERY nicely today.

I hope to go out again tomorrow. I keep meaning to get some videos, but I just forget about it when I am flying it. I'll try again tomorrow!

Folks that saw it today for the first time were all over it! One guy I didn't know was asking a million questions. A newbie asked how much it costs, and another fellow said that it would be a crowd pleaser at the electric only fun fly on the weekend of the 17th-19th! I really look forward to that!

Oh, and if I didn't mention it anywhere else, here is the complete mods of the stock Funjet airframe:
3mm (I think) x 1mm carbon flat on the trailing edge of the elevons. Glued with CA.
2x magnets on each side of the canopy.
More glue on the control hardware to stiffen it all.
Dremel work inside for the 6s battery.
That's it!
It's pretty cool to hammer it down the straights for a second or so and then let off and head for the stars. It gets pretty small just coasting up there!

All fun!
Kent

[19000rpm]

Sounds fantastic Kent. Good to have you back and flying again.

[Gabe]

Jimmeny Crickets! That's killer! You gotta get a radar reading on that thing on a straight away.

The guys say a minimum of 2 second WOT on a straight away (no dive) before the Doppler gun. Do one both ways if you get a chance for wind.

Dang that's cool!

[akent]

I went out today, but the winds and intermittent rain were crazy. There is a tropical storm moving in, apparently.

I didn't fly either Funjet today, but I did fly a new 3d machine, the Hyperion Sniper II, only to burn out a motor. I had too much prop for that little Turnigy 2830-1050kv motor turning a 10x4.7 APC slofly on 3s.
This Sniper II is made from EPP foam and is an AMAZING flyer! I'm flying the smaller one. I was actually hovering the thing in 25mph+ winds! It sure zipped away in a hurry in a hover! I tried my first inverted flat spin today, too. I forget what that maneuver is called. Anyway, it kind of did it, but the motor burned out about half way into it. I dead sticked it in with no issues, as it's EPP! It smacked a little, but it just bounced off the ground.
If you get one of these, toss the landing gear. The CG makes or breaks this machine. Set to the manual, it will be docile. Set the CG back an inch or more and have enough power and this thing will flip on itself! It's really stable in the wind, too! I can't believe this thing is foam.

Hey, and mine is running HXT-900 servos! Man have I stressed those in this thing! They are holding up so far!

This is now my favorite plank. It is incredible in the wind, does 3d like nothing else, is indestructible EPP foam, and is amazing. The only downside is the paint on the thing must be water based. Ugh. It's washing off by just touching it. Oh well. Eventually, I'll give it a bath and repaint it with real paint!
===
I did hover the Exi-500 in the crazy wind and that thing never ceases to amaze me. To heck with the ES600 Esky. I'm going to sell that heli one of these days if I can, maybe to Nuttcaze. I don't like that heli much any more. The Fly Mentor doesn't like it either. Well, it doesn't because I don't.

I have a complete ES600, tons of spare parts, one complete CNC kit and one complete carbon fiber kit. One of the motors smoked, so I only have one spare besides the one in the heli.
This is a sad thing.

Sorry to ramble.
Kent

[19000rpm]

Kent, why not start a thread on the hyperion sniper 2 over in foamies. Give us all the details.