gabork73

Hi!

This is a video how a Funjet can blow up in the air cause of overspeed.
Its a bad quality video without sound sorry for that......
http://www.youtube.com/watch?v=mca42oZF06s
gabe

gabork73

There is a video we were testing 3 cell batteries.
The max speed was 230km/h.
http://www.youtube.com/watch?v=ruNsZ...e=channel_page

blanik213

Hi all I am new to rcu but not to the topic and glade to find there is another forum besides rc groups. Hey garbork73 nice looking FJ what is your AUW and is the entire FJ glassed? fidy$trainer you hit it on the head,it would be great if there were a sanctioned top speed event for stock and modified foamy's. I think a lot of useful information could be shared that would defiantly lead to establishing a new terminal speed record.

moparmyway

OK, I tested and here is what I got

183.2367 amps on Fluke 98 Oscilliscope with 80i-110s clamp on AC/DC
183.2355 amps on Fluke 87 Multimeter with i410 clamp on AC/DC
183.24 amps on Eagletree 150amp Datalogger V3

I guess the Eagle is just as good as anything Fluke has. All of my equipment is calibrated by Fluke annually.
Testing was done on Medusa 28x56x2800 with Graupner (balanced) 6x6 prop on NEU 4s-5000 (30/60c) battery fresh off the charger with 10% battery discharged with BOTH clamps attached to battery positive lead. All readings were recorded at the same time.

Gryphon

gabork73

The NEU and Castle Creations web sites show the 1110/1.5D as 6200 KV not 5200.
Same with their online simulator, and same from an excel spread sheet that I got directly from Steve NEU.

So if we are to assume there is a type error on the motor label, then let’s assume it is lower KV than you believe...maybe 1110/2D 4650KV, or 1.5Y 3350KV.


I have very good amount of experience testing motors and I firmly do believe that the 5000-6000KV motors can handle that sort of AMPs, but even if your modified ESC can handle it, I just have a serious problem with your choice of battery.

Your battery should hit Low Voltage Cutoff in a matter of seconds...not long enough for you to reach top speed. Looks like you are doing the dive bomber technique. In your case the prop size can transfer the motor’s power to air very well...it’ just that the battery cannot keep up with motor demands....I would say the same thing for 5000 30C/60C cells.

Yeah, I know how to multiply the 5Ah X 60C=300A those are just blatant lies from most battery manufacturers and so many of us have seen battery damage after running just a little over(extra 10-20%) constant AMP rating of our batteries.

How come your ESC did not cutoff at 3V per cell? 11.6 / 4S = 2.9V/cell
In a matter of seconds your pack drops to those kind of voltages,.....don't you think that causes damage to battery pack?

It may be plausible that you have a Funjet at those speeds, but if it cannot maintain it for more than a blink then I don't know.

Folks are running 4S-5000 , 5S-5000 in their fast funjets and I know there are some real GREAT setups with more powerful motors than yours in the works. 160 gram NEU, Medusa and even 36mm ARC. Those planes will be able to stay at those speed as long as the eyes and pilot skills allow.
In your case, the battery will now allow.

I will not debate what sort of power you made or what real amps are.....because even if your numbers are correct that is still not a proper setup.

I've seen half of your AMPS damage top quality 5000 cells.

Given your prop and KV and 4S you should see much more amps than what you saw, only reason you didn’t is because your battery just can no handle.

You might see a dozen other people say the same thing.... I know better because I have seen what can be done with 5000 25C cells and what sort of draws puts them down.

5000 25C will outperform a 3300 30C.
I saw your video for 3S……I lost track of the number of times that it seemed to cutoff…when a setup is cutting off on 3S it will cutoff even worse on 4S given same prop.

Either way I assume on 3S you were running less amps. On 4S there is now way that your battery is keeping up with demand.

Given a much larger 4S, you might damage your motor with that size prop…so lucky for you that the under size battery is letting your motor live.

Earlier comment on pitot tube position was regarding disturbed air, not wind. Generally people install it in the nose or half way across a wing’s span.

It can be checked against radar on a day with no wind to be sure…up to you.

If you are not able to accelerate and reach your top speed in level flight then I would not call it a 167 MPH setup...not that it is my place or job to say who goes how fast...that is just my 2 cents.

Either way it is one very fast setup.

In a PM I’ll send you a link to a thread with lots of 130+ MPH Funjets.


Keep having fun and thanks for sharing your setup,


Gryphon

gotboostedvr6

gabork73

I'm not even sure where to start but your lipo seem like a good place.

There is NO way 3300 cells can take this beating of death you are laying down. running at under 12 volts proves my point. Not to mention 3300 cells running 232 amps would die in 4-6 discharges.

A 6,200 kv motor would be over propped with 6 x 5.5 on 2s! let alone 4s.
2s would run over 150 amps, 4s would be WELL over 475.

Are you sure your motor isn't a 1.5 Y ? that would explain alot!

The location of the pressure port for the how fast system is in a high pressure portion of the airframe and is likely showing a higher speed then actual

You could also post up a flat and level pass 300 feet in and 300 feet past the camera that is flat and level the whole time and 30 feet off the deck so I can doppler it to prove the speed.
I really hope you prove me wrong with the doppler! if your speed really is 167 that would be insane!

I have alot more to add but i am exhausted.

tIANci

Okay ... I am so tired of this Need4Speed that I will ensure that I got the ultimate FJ. Tonight I will bring out my FP EVO25 5S 4,900 mAh packs with a nice hot NEU motor that I will beg Steve to wind for me. It will be running on a 10S set up and turning a 8x8 prop at no less than 35,000 RPM giving me about an actual speed of 200 mph. I will be using a specially designed ESC from CC/Jeti.

Actually, would it be better for me to just purchase a rocket?

gabork73

Is that Medusa motor is 2800KV?
If Yes then put a little bigger prop on that and measure it again.

gabork73

Hi folks!

Next week I will start to bulid one.
Iwill document the building process and the flying,static measuring with pics videos and close flybys for doppler measurements.
I dont want to prove anything because its unbeilivable for me too...............but works.

gabe

chippedprop

gabork

Well seems that gabork73 has shaken things up a bit.

Nice job on the plane. I can tell that you have improved each plane as you learn from you past mistakes.

I would suggest that you drop the diameter of the prop to reduce your amps. You may find that you can go faster longer. Now you are only a drag racer. 4 seconds down the track and your done. Not much fun in may humble opinion.

But all said your a speed monster for sure.

TRY to keep the speed numbers real and the equipment numbers also. Real science is more fun then science fiction ....get my point ?

Why toast equipment just to be the fastest. Just doesn't make money sense to me.

Keep posting and we all may learn something. We may be able to help you too.

My latest FJ is getting the final coverings and canopy painting as I type ( paints drying) weather should allow me to test Thursday.

I'll post pictures shortly.
Chippedprop

gabork73

Hi!
I rtied to put smaller prop on it beleive me I have abou 20 diferent size and make of props just for tis application.
One more thing to be cleared:I buid those planes not just tobe fast all of them built for TOP SPEED.
Every one of them improved a little till now.
If an electric plane built for top speed and can handle full throttle for more then five seconds then something is overconstucted.
Top fuel car racers rebuild there engines ater every race.Only runs seconds to be the fastest.
Formula one racecars getting new engine after every second race cost them a serious money......Yust tobe the fastest.
So I know exactly my battery wont last long and every part of this package can blow anytime.Thats how it is I choosed it.
Some of You will understand it some dont.
Some guys are flying around with 6 or 7 cells on full throttle till the esc cuts......they can do better than that,but they dont because its fast enough for them.

gabe

chippedprop

gabork73

Ok you got my point. Turn and burn. See if you can get some video.

Make sure your vid operator turns the auto focus off. Prefocus on an object you think you will fly out to...then turn to manual focus. Use the zoom on the camera to keep the plane sized into the frame. This way your plane will be in focus. Here's and example.
http://www.youtube.com/watch?v=zMfaOSph9OE

These are turbine jets running 190 to 200 mph. I'm standing 25-30 back from the flight line. I can't wait to see how this turns out.

Way to go...fast
Cp

chippedprop

The new FunJet is finished!!!!

Finished weight with a 3 cell 2200 ma 30c battery.... 22 oz..... dead on my target weight.

All color is low temp hanger 9 cover.
The fins are same size and design as stock only 1/8 lite plywood, covered
The front canopy is made from a 3 liter soda bottle rev. painted ( inside) screwed down. Notice the flow thru vent looking from the rear of the canopy to the nose.
Rear deck is flat plastic rev. painted...screwed down. I most likely will have to add a intake air scoop for the ESC as I had to on the last FJ. I'll see during testing.
Carbon fiber tube(s) run nose to tail and wing tip to tip. The wing tanks have been sanded to match the surrounding wing.

The motor is a special custom made 2900kv outrunner by MicroDan. It will make the this plane run over 104 mph in 4 cells 2500 ma 20 c for 4-5 minutes. It will have unlimited vert. on 4 cells as did it's brother.

Prop will be APC CF (new) 4.75x4.75 and 4.75x5.0 ( new) also CF
Hoping a little stiffer prop will get 1-2 more mph.
On the last plane I did have a shield covering the mount area, but I found it was blocking to much cooling air. With the shield off it runs better due to increased cooling.

gabork73

Hi!

Grat for that and thanks for the video hint.

gabe

Fidy$Trainer

My Feedback: (1)

Hey congrats great looking bird you mention 4S in your description but the picture you posted below is a 3S? Are you using the 3S or 4S? If that's your battery your claming 270km/h on 3S???? Just wondering if I missed something here.

Fidy$Trainer

My Feedback: (1)

Hey guys,
Just got my 5S. Anyone know if PollyQuest is any good? It was a pretty expensive battery bought on impulse. I have a bad feeling I'm going to have to get a much bigger ESC or much smaller prop than a 6x5.5.

moparmyway

Well, normally I would say something like NO WAY.................
But I have a question instead....................
Have you run a Medusa 28mm motor with more amps than that yourself ?

gabork73

Hi!

I never had Medusa motor,I know its a top of the line,but air cannot flow trough that motor becaused it hase a closed casing.
You can cool it outside,but the air canot go inside.
Thats why I choosed NEU.

gabe

Gryphon

gabork73,


You are talking about the original motors:

http://www.medusaproducts.com/motors/028.htm



But for last 1 1/2 years or so the V2 has had cooling air vents in both ends. Plus some other mods for increased efficiency for extra $9-$11. See pics:

http://www.medusaproducts.com/motors/028-V2.htm

Keep up with the times.

Moparmyway has (4) NEU 1115 motors, (3) Medusa 28-56-XXXX motors and (3) custom made secret motors that will soon be published....all (10)160 gram top shelf motors….3-4 more planned {he’ll hate me for listing his stuff}
*** He knows what he is talking about.

Telling him to run a bigger prop didn't sound that good but he took it well.

Listen, we all wish you the best....we want to see each and every person break the record over and over in a way to have consensus and acceptance of everyone….Doppler pass after you come out of a dive very far back is acceptable because if you come out of the dive too close you would have gained excess speed from the dive…if far enough you get a chance to get up to speed from dive and will bleed off any excess speed before you get close….so do the dive far far far away from recorder and no one will cry foul.
Make sure to stay level for a about 2 seconds after passing recorder …that is where parallel packs can help you avoid cutoff as fast.

I have a drag racing background, so does moparmyway and your drag racing analogy was found very amusing...honest....[sm=thumbup.gif]

A suggestion for your consideration would be to keep using your 4S pack but at least parallel it with another 4S of any size... since it is not in series they don’t not need to be identical packs.,,, then again I think something bad will happen to another component after that.


Gryphon

moparmyway

Well, at least you "only" listed my 28mm inrunner motors

I left out the $%#@&*%$#@ in my above post, but I kind of knew he NEVER ran that much current in a Medusa. I MUST give NEU "Y" wind motors a chance now, its only fair !!!

__________________________________________________ __________

Gabork73,
I thought I pushed the limits, but I must say, at least you admitted that your setup is EXPECTED to blow up at any time !!!!

Most people (including myself) do NOT want their $$$$ just blowing up, but I guess there is a favorite color for everyone, after all, Crayola still makes 64 colors for a reason !!!!

gabork73

Hi!
Yes I made a mistake put a wrong picture .
Im flying it with 4 cells.


gabe

chippedprop

Maiden the new FunJet at lunch. Everything worked great. This one flys a little diff. then the last one. I guess each plane has it's own style. Of course it has been a while that I have flown the FJ

Only mishap was on a high speed pass......... the covering on the bottom fuse ripped half off. Scared me to death!!!! Right over my head 100 ft up!!!!
No problem. I usually use extreme packing tape for the skid plate..so I have already replaced it.

Used a carbon prop.. first time I have used one. I'm not sure I like it. It was WAY out of balance new and I had to remove a lot of material. I'll run a grey APC 4.75x4.75 later today.
Motor came back ice cold after each flight including 4 cell wot most of the time. I just love the MicroDan motor
I will add a air scoop for the esc as it was a little warm on landing. I have think about a cooler looking scoop vs. the 1/2 plastic spoon I used on the last one. LOL

FUNJET is back in the air.!!!!!!!!!!!
Chippedprop

Gryphon

chippedprop,

Congratulations brother. Your new Funjets looks very good.

I covered my Stryker with red Ultracoat once. I liked it, but I did have to reheat the covering several times to get it to stick again and to take care of bubbles.

I hope yours lasts more than a couple/few dozen flights.

Either way, I am happy that I tried it and it was a fun experience over all.

I look forward to seeing you at the Fly-in event next week.


Gryphon

Fidy$Trainer

My Feedback: (1)

I don't recall seeing any pics of cooling mod's to the FUSE. I've heard of a couple spoon scoup? Does this go on top? I had thought of putting a couple of circular holes on the bottom of fuse for cooling but now I'm thinking a couple of holes between the cannopy and rear section right where the ESC sits. Anyone have pics than can share on some cooling mods. I have two heat sinks on the Medusa on stock motor mount but it doesnt look like a hole lot of air is going to get through thier.

Gryphon

Fidy$Trainer,

Ask the folks or see for yourself if the inside of the foam tail cone can be trimmed/sanded down a little for more airflow....I'm talking about rear of fuse inside of the tail cone area where he motor sits...can you make that area larger diameter by sanding down the foam on the inside a little?

Verify from the folks that it is possible before doing it...if you go extreme on the sanding, maybe you need to fiberglass the area or something.

I bet some of the people here can guide you on that.


Gryphon