I have two of those motors. Not quite as good as a Mega 16/15 and the kV is between a 16/15/2 and 16/15/3.

The FJ is a fairly large and heavy plane for that motor and needs a prop larger than a 4.1x4.1. The larger the diameter the easier the launch and the larger the pitch the higher the top speed as long as the prop isn't cavitateing. For the FJ at least a 5" diameter is really needed unless you have a good arm and really good at launches. You'll want at least a 4" pitch for decent speed. Then you have to make sure you don't over load your motor, ESC, or battery.

A 28x36mm motor like the 16/15 and 2835 3900 motor is almost too small to get good performance from the FJ as they are limited to about 400 watts.

A 28x45mm motor would be better as they can pull 600+watts.

On the 2835 3900 motor you should try a 4.5x4.1 or the 4.5x4.5 you mention. Yo ucan try a 4.75x4.75 and make sure you have good cooling as it will run hot.

All this will pull between 45 and 60 amps so you'll need a good ESC and battery. At least a 30C 2200mA battery.

First let me introduce myself. I am Barry from Powdersprings, GA. One of the Geezers at my flying club has one of the FJs. I am thinking my next plane will be one. I will probably get it from Grayson Hobbys with there [link=http://www.graysonhobby.com/catalog/product_info.php?cPath=2_90&products_id=463]combo upgraded motor/esc[/link] and this is the [link=http://www.graysonhobby.com/catalog/product_info.php?cPath=22&products_id=645]upgraded power combo[/link]. The whole package delivered to my door for $125. I will do a lot of the mods you guys described in this very long thread and hope to report back on this set up in the next month. Comments and suggestions are always welcome.

I am also considering these [link=http://www.graysonhobby.com/catalog/product_info.php?cPath=16&products_id=695]servos[/link] . Servos is always a subject and I am looking for the ultimate servo. Micro size, bullet proof gears, digital, and it's free. The last isn't going to happen but the other options are getting closer just the price factor to consider. Oh, I am Scotch heritage so I really like a great value for my money.

i use the futaba 3114 servo's there strong light weight and super fast an about 14.00 bucks. I have also only striped one and I have been flying them in the funjet for a few years now

Hi guys, Im fairly new here @ RCU and wanted some opinions on my funjet setup. I had a stryker brushless 1880kv, 6x4 prop, thunderbird 36 esc and a 2200mah 3s lipo on it and it flew pretty nice. About the same speed as a c model stryker. I have a Heli-max 6 pole 2580kv that bolts right up.. I was thinking a 5.5x4.5 or 4.75x4.75 prop wouldnt over amp my esc.. What do you guys think the performance of that setup would be? Any helpfull suggestions would be appreciated. Thanks! ..rockitboy.

My Scottish mother in-law would chew you out for saying this, highly incorrect as Scotch is a drink not a nationality.

Faster speed and more fun, do it!

Yes, she would, but Scottish sounds so girlie. Of course the Scottish men wear skirts called kilts so I should after all these decades get use to it. I quess I can change it to Scot and that might keep Evan off my Ar*s.

She says Scottish is the adjective, Scot is a noun and not correct either. Hey I'm just the middle man here....

Since this has nothing to do with the thread I think you are just a pot stirrer.

Yes well, Have fun. Thanks for all the help scotty!

Sorry about that. I think if you have it on hand and it doesn't cost anything then try it as long as your watt meter/amp meter keeps you out of the danger zone.

You should be Ok. on th FJ you should be in 70-80 mph range as the FJ has less drag then the stryker. Most ESC have a +5/10 amp buffer built in to them.
You'll like the FJ more then the Stryker.

I would suggest you check the c rating on the lipos 20 + equal better performance from the motor.

If you make a new FJ, pm me and I'll give you some suggestions.

Cp

new video coming soon.

rockitboy

make sure you turn on the box to get PM's (private messages) as you get get help form others who sometimes don't want to post on the thread.
chippedprop

Hi everyone, I just got done building a fj. I used the stock speed control, battery,and motor out of my stryker c. What can I expect for top speeds?. I am also running the stock 6*4 prop off the stryker. Any help you guys can give will be very appreciated. I am going to upgrade the sc and motor down the road, But it was laying in the garage so I used it for now.

Hi all.

Just got a FJ today with the grayson upgraded outrunner. How is this to be mounted as the manual is for an inrunner? This is my first build. Have been flying strykers for 12 months and need more speed.
Any help will be great.

My motor is an out runner, just had to reverse the shaft

If its an outrunner its best to mount it OUTSIDE and NOT inside. If mounted inside there is a risk the rotating can will clip the wires to the ESC unless you can safely anchor it.

Thanx.
Just mounted the outrunner did all the test things and powered her up.

Well all went well then throttled up and all smoke!

Now I'll have to get a new ESC. This one went wrong. Was correct initialised and as soon as I increased the throttle it started to smoke so I disconnected and now it's not initialising.

Don't know what went wrong.

Any suggestion? or help if ESC was faulty.

dic181,

Sorry to hear about your smoked ESC. Please keep me/us posted on what you figure out went wrong. I was planning on buying the exact same combo.

Thanks,
Ty

Hi all,

*** What is the fastest Funjet that you have heard of? I mean how fast was it clocked?

Any links?

Do you recall the setup?

Any links

Where did you read about it if you remember?



I'm curious to see if it is the same one that I read about.

Any help will be appreciated. Feel free to reply in a PM if you prefer.


Wow, I have some reading to catch up on...keep up the good work everyone.

Gryphon

Hi guys,

Need help.
Medusa 028-040-2500V2
60A Esc
4 cell 2200 mAh 25C
Had APC 5.5x4.5
Now Graupner CAM 5.2x5.2
Although more amps static with the 5.2x5.2 speed is not better. What do you recommend? Can I go up to 6S or will I be too heavy?
I need speed. An it doesn't seem I get it. Last time I clocked it at 105 mph with the 5.5x4.5.

Thanks

Pani ... I gone 6S and its a waste of time, the extra speed is not that much compared to the increase in watts/amps. Also the plane handles like a pig ... keen on that? If you want speed, get a new plane. The FJ is not made for speed. Many who flown her on 6S will never mention about the handling etc but only want to boast about speeds. Rockets are much faster to be frank.

Basically, because of the FJ's design you will be spending a lot of money to increase power so as to overcome the fuselage's innabilities.

tIANci,

Hello there my old friend. I hope you've been doing well. We need to catch up on some PMs.

Your not so great experience with 6S is documented by you on page 7 and 8 of this thread.
Just remember that was not a good combination nor was it a good motor as per your comments,..... so not all 6S setups are bad.

_____________________________

pani,

Forget the advertised AMP rating of your motor. People run that motor on 65AMP to low 70A range on regular basis with no issues. I would rather see it kept closer to 60-65A for daily use, but some guys are pushing it harder.

You are under propped. You can see HUGE gains in power and speed with use of larger diameter prop and/or increase in voltage.

I know 5S would be awesome setup for your motor in Funjet if you can keep up the amps for Jaw dropping climbing and speed.

6S given your KV becomes a little questionable, although my simulation says that if you can swing 5X5 on low 70A range that it would go faster than a 5S setup. Still I rather see a 5S 2500-2700 pack at 30C.

It is not all about more power, if prop size is not there you might not have enough thrust to overcome the drag in order to go faster although you may have plenty of prop pitch speed.

Being thrust limited does not come into play till at higher speeds, but for sure a small diameter prop (on a given pack) will have reduced acceleration, harder launch and reduced climbing (as compared to a larger diameter prop)....you must have felt its reduced acceleration when you went to 5.2X5.2
I suspect that it could fly a little faster with 5.2" prop but you need a longer run to get up to speed.

On 4S motor can handle 6X5.5 easily, so question becomes your ESC, and batteries and how far you are willing to push them....besides the Funjet's ability to provide cooling air to motor.
A few full throttle runs and some throttle management would be fine when combined with a heat sink. Medusa makes the best heat sinks for 28mm motors and is available in 2 lengths.

No question you can fly at 140 MPH with your motor on that plane...Question is how much faster.
Do you have better batteries and ESC?
Were you going to buy 6S or run (2) of your identical 3S packs which are in same exact condition. If you were going to buy new pack(s), then consider 5S good enough for 70A even if you'll run a little less Amps.

Usually I hear weight complaints when a person's power to weight ratio was poor, at times due to a huge huge huge pack for only 800W or when a person is used to flying a Funjet slow and does acrobatics at low speeds or land at real slow speeds…when those guys increase Funjet weight, they are disappointed.

High speed:
It is a compromise and also people get used to anything in 2 weeks. Then they wonder why they didn't do that combination sooner for that new realm of high speed fun, the grin will not leave your face. Make sure the rest of your plane can keep up with quality servos/rods/clevises and any strengthening mods needed, your skills and being able to handle greater financial losses in case of a mishap.
The 72 MHZ receiver needs to be placed far from ESC and motor and UBEC. If 2.4 GHZ, then stay away from AR6100 and AR6300 in favor of AR6200 and AR7000, possibly the new AR500.

Right now, your awesome motor is bored in tears at those medium amps.

Want to chat with others who fly same motor at high amps, then send me a PM for some contact info.


Gryphon

Gryphon! I am well and all is good here. So what blistering plane are you getting high on now? I decided to get my 40 sized Lazy Bee up and have been cruising around at 10 mph. Hehehehee ...

What I used was an El Cheapo motor. I was mainly getting at is not really about the power and speed but more on the handling. I cannot imagine using 3S 3,700 mAh packs like what some used. For me it was a mere 1,800 mAh pack and I felt the higher wing loading that really took away the nice flight characteristics of the FJ. Nevertheless, I still find the FJ as one of the best pusher jets around. You can go from 3S to 6S. From mild to wild to MAD.