Another GO-FAST!

[akent]

Well, I was reading about the Strykers that folks are building and modding. Then I found a reference to the Multiplex Funjet.

It is supposed to be faster than the Stryker and handle at least as well at speed, so I bought one!

It was $73 for the kit from Tower with everything but electronics. I had a discount, so it was a little less.
www3.towerhobbies.com/cgi-bin/wti0001p?I=LXNXV5

It sure looks good and the foam feels very strong. Perhaps one of the coolest parts is the motor mount is fully adjustable up to 5 degrees in any direction!!

Here is a review of it from RCfoamfighters.net. He's using the same motor that I'm running in my Stryker, and says he thinks it's over 100mph with 4s! Everything but the power system is STOCK!


I have this one on the back burner until after I build the 'Dark' Stryker!
Kent

[Gabe]

Sweet! I hear good things about the Fun Jet, especially hat they can handle up to 7 or 8s batts. I'd think about talking to Gryphon about a Mega Motor.

[19000rpm]

I've been looking at this plane for a long time. I guess it's time to put it on the short list.

[akent]

I need to take some pics and vids. I didn't because I didn't believe that this could be much better than the Stryker.

Well, it is.

I flew mine today with the electronics and power from the smacked in Stryker. With a 3s battery, it is noticably faster than the Stryker!
I tried to prove that by giving a fellow my radar gun, but he couldn't get a reading on it.

Battery 2: 1800 40c 4s.
You talk about INSANE!
Folks said it was at least as fast as the really fast EDF that one fellow flies there, that goes well over 100!! WOW!
It did go from left to right in a millisecond and went from 10 feet off the deck to a dot in the sky in less than a couple of seconds. That part blew me away.
This thing is insanely fast, but I don't know how fast yet. The radar man could not get a reading here either. I need a new radar man, or a new radar unit!

I do know that the motor comes down VERY HOT with 4s. TOO hot, maybe. I guess I'll see how long it lasts! The ESC and battery come down only warm.
After the first 4s battery, I did a WOT pass, then I flew very slow for a while. Then another WOT pass.

It still came down HOT enough for the mounting bolts and prop mounts to be hot. Not untouchable, but close. HOT.

What I'm running:
Turnigy 2836/2350kv outrunner motor. (Edited for the proper motor number. Thanks 19k!)
Turnigy Plush 40 amp ESC.
2200ma 30c 3s batts.
1800ma 40c 4s batts. (These are about the same size as the 3s above.)
6x4 APC (both sport and E) I think the E is faster on this one!
Kent

[19000rpm]

Very cool. Still haven't picked one up yet. I've got a few projects to complete first.

[akent]

I have been playing with props a little on this plane.

The APC 6x4E that I originally ran is a 'Speed 400'. I don't know if all 'E' props are.

I tried an APC 5x5 also a 'Speed 400' and it was noticably faster, but it lacked as much vertical and was harder to launch.

I tried a 4.75x4.75 same style and it was even worse. The RPM's sounded about the same as the 5x5.

I think these planes need larger props. I was going to try a 6x5, but it drew too many amps, as it started to slow quickly after a spinup. It got REALLY hot very quickly just with a bench spinup.

So, the 6x4 is the sweet one for me. It's not the absolute fastest, but it has wicked verticals and goes somewhere around 100. I will hopefully know how fast it really is soon! Noone can seem to get a reading with my radar gun, and I haven't been able to get a reasonably close video pass.

I do still love this little guy and so far the motor is holding up! I now do a WOT pass and then slow down for a couple of passes at half throttle or less. Then another WOT pass. The motor now comes down very warm, but not blistering. You can at least touch it now.
Kent

[19000rpm]

Sounds like that motor is perfect. I'm going to get one on my next order. BTW, isn't that a 2836 2350kV outrunner?

[akent]

Oops, yes, it is the 2836. I think the 2835 is an inrunner with less power, if I remember right.
Here's a link to the right one:
www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=7993

I hope they get them in stock, as I would like a spare!

You can also install up to a 36mm diameter motor in the stock mount!!! They are running the Turnigy 3648-1450 on 5s to hit almost 150mph with a 7x6 prop! That sounds very similar to a 500 heli motor. I have a 500L Align motor that is 37mm diameter. I think it would fit but it's heavy... Humm...

I can't wait to hear about the smile on your face when you build one of these up!

So far, I have done absolutely nothing to the airframe. It's 100% stock. I did add some black packing tape to the bottom so I can see it a little better. Valspar plastic paint seems to work well. I just painted the wing tip tanks so far and it didn't eat the foam. I think I'm going to paint some bright stripes on the top one of these days.

Oh, and to my amazement, I'm running HXT-900 servos on this thing without problems so far! I don't try to pull out of a vertical WOT dive, but I do pull out of shallow WOT dives coming onto the straight away! They are holding up so far! I am keeping an eye on them, though. It will be interesting to see how they last! Actually, I have had zero failures with the HXT-900 servos with anything. I am running 25 of these now on all kinds of planes.

Also, I'm still running with the motor angle at 0. It doesn't pitch up or down when you nail it from level. It just GOES!

If you run a 3s battery, this plane likes the APC 6x5.5E prop a lot! It is fast with great verticals, too, but not like 4s with the 6x4!! You'll see!

Fun stuff!
Kent

[akent]

I just installed a speedo into the Funjet.
While it was sitting, I decided to plug in my Watts-Up meter.

Here's the results (4s, 6x4 APC Speed 400):
15.1v
55.3 amps
818.49 watts!
My optical tach won't read consistently. I think I need a really bright light on the other side, so I don't know the rpm. It's a LOT, though! It made my F86 fly off the bench, broke one of the tanks. UGH...

I need a bigger ESC! This is only a 40a Turnigy!

I'm impressed with this ESC holding up with that kind of overload! I have an 80 amp on order now. Interestingly, this 40 amp version doesn't get hot at all. It is just barely warm. Humm...
Maybe a little more power with a bigger ESC?!?
Kent

[19000rpm]

I like those HX 900 servos too.

I think I'll stick with the 2836 for now. Where I fly I'm surrounded by trees and I'm sure a faster plane, that small, would be out of my field of vision too quickly.

What do ths Darkside guys say about reinforcements for a 150mph verion?

[akent]

Jun 30, 2010 5:36:54 GMT -6 19000rpm said:

I like those HX 900 servos too.

I think I'll stick with the 2836 for now. Where I fly I'm surrounded by trees and I'm sure a faster plane, that small, would be out of my field of vision too quickly.

What do ths Darkside guys say about reinforcements for a 150mph verion?

I also really think that the 2836 is plenty! At least mine is so far!

From the video on U-tube where the RC Foam Jet guys put the big motor in there with a 5s battery, it hit over 130mph at a huge angle to the radar gun, they only showed a single layer of fiberglass inside the rear foam by the motor mount. That's the only reinforcement that I saw!!! I am pretty sure they later hit almost 150 with the same setup. Nuts.
I honestly have not read the dark threads much, as I'm just so tickled that this thing flies like it does with what's in it!

I had a 60 amp ESC here that was in my electronics box that I forgot about. It's a Turnigy that looks, sounds, and programs exactly like my Hobbywings do!
So, I installed it in the Funjet and did a run up. It draws essentially the same power as the 40 amp one did. That is amazing that the 40 amp one held up like it did.

Here's a couple of pics of the new ESC install:
You have to connect everything up and feed it in from the backside. I made an extension that is a little long, but it lets the ESC go in the front until it's mounted. It's kind of hard to explain.





Here's everything mounted including the speedometer board in front of the receiver, and the pitot tubes mounted in front. I didn't do a very good job of getting them perfect...


There is a lot of room for the battery:


Speedometer board:


Here are the black visibility stripes I added to the bottom. They help, but it needs more:

[19000rpm]

That speedo is really cool.

You might want to paint the vertical stabs red to help with visibility from the top side.

I've got the motor on stock alert at HK.

[akent]

I agree on the red vertical stabs. The only problem is that they protrude down below the elevons, so they are kind of hard to paint once installed. I think I'll try anyway.

I just pulled out my new Funjet kit and guess what.... My Align 500L motor bolts right in and has PLENTY of room to mount in there!
This motor weighs 215 grams and has been clocked at over 2kw.... That's about 30 grams heavier than the 150mph motor (Turnigy 3648-1450). That's heavy.

Not yet, Kent, not yet....

Here's the new Funjet fuselage with something bolted to the motor mount...Humm...






Might be as good as the Turnigy for 150mph??
Kent

[19000rpm]

If you mask off the fuse and wing and just leave the fins exposed they should be easy to spray.

I think I'll stick with the teeny weeny motor. When I told my wife about the Funjet and 100mph she forbade me from buying it...We'll see about that. ;D

[Gabe]

Wow, I've really missed the boat on this thread. When you get a speed reading on this thing, or you get a doppler on it, let me know.