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Old Oct 17, 2012, 07:31 AM
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I took the Radjet out today again..... (Turnigy 2826/6-2200kv motor)

I had broken my APC 5x5 prop (I have plenty) and I decided to throw on a TGS Sport 5x5 (which I have plenty of also)......
WAY less power!!! Clearly visible.... maybe as low as half the air speed! I would say much to the stock Radjet speed (run just as it comes) on 3S.

"5x5" is not "5x5" apparently!!!

I didn't have time to try 4S, but I would say on 4S this would come out somewhere between the APC on 3S and 4S. So it would probably run the motor at an acceptable power level (Watts) for ongoing 4S use, compared to the APC being excessive power (Watts, Amps) for the motor to last at.
I will try that tomorrow if I can.....

I also have APC and TGS Sport 4.75 x 4.75, so the TGS will be useless for sure, but the APC 4.75 x 4.75 should also be a good 4S prop for it.

But that difference (drop) in the TGS Sport prop was a big surprise!!
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Old Oct 18, 2012, 01:11 AM
Reap the wild wind
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It's odd that you are having such poor results with TGS props. They are also branded EMP and in most test results Dr Kiwi found them to be superior to APC.
http://www.rctoys.com/pr/2012/05/07/...ng-propellers/
Here is a video that might interest you
EMP vs APC 6x4 props (5 min 57 sec)

Andy
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Old Oct 18, 2012, 02:37 AM
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Interesting that he has a 2200kv motor (same as mine) but using a 6x4.
He is only getting about 80kph (both props), versus my APC well over 100kph. TGS probably 80kph or less.
The Radjet is probably heavier than that "Flat slab" F-16. (?), but might be more streamlined.
For a start this lack of speed seems to suggest that the 6x4 is over-propping that motor - or the design/construction of the F-16 is very inefficient and making that even more bogged down.

I will do a better tests day, with testing all the props, this weekend. And with GPS and/or RCspeedo checks too.
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Old Oct 18, 2012, 04:19 AM
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Quote:
Originally Posted by PeterVRC View Post
Interesting that he has a 2200kv motor (same as mine) but using a 6x4.
He is only getting about 80kph (both props), versus my APC well over 100kph. TGS probably 80kph or less.
The Radjet is probably heavier than that "Flat slab" F-16. (?), but might be more streamlined.
For a start this lack of speed seems to suggest that the 6x4 is over-propping that motor - or the design/construction of the F-16 is very inefficient and making that even more bogged down.

I will do a better tests day, with testing all the props, this weekend. And with GPS and/or RCspeedo checks too.
Im using the same Turnigy 2826/6-2200kv motor on 3cell in my Radjet with an apc 6x4 and it is a lot faster than the stock setup.
Have you compared an APC 5x5 to a 6x4 prop?, I might have to get myself a 5x5 and give it a go.
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Old Oct 18, 2012, 06:39 AM
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There was a link to a motor/pro chart in the article. It shows the 2836-1350kv does about the same on 5x5 TGS/EMP as 6x4 APC.
But the 3S Radjet 2200kv was as fast, or faster than stock on the 5x5 APC. Just lousy on the TGS 5x5. I will try the 6x4's also (have those in APC and TGS too) but I am guessing the 4.75 x 4.75 could be best.
But anyway, will need to do all the Amp/Watt tests and then go and flight test them.
Even a different battery (size and/or C) can change things too, so you need to keep all the records of all items and results too.
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Last edited by PeterVRC; Oct 18, 2012 at 05:18 PM.
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Old Oct 18, 2012, 03:59 PM
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Just got my hands on an apc 5x5 and will test today against a 6x4 on my brand new un maidend Radjet, my other one is stating to look very secondhand
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Old Oct 18, 2012, 06:02 PM
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Looks good harlyquin!!!
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Old Oct 18, 2012, 06:50 PM
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Thanks mate, hope it still looks that way after today.
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Old Oct 19, 2012, 02:35 AM
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ok ive tested my new radjet with both the APC 6x4 and 5x5 props.
It was to close to tell the difference in top speed but the main thing was it was way easier to launch with the 6x4 so im sticking with that.
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Old Oct 19, 2012, 05:27 PM
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Originally Posted by setxws6 View Post
Looks good harlyquin!!!
+1!!!!
That's your second-gen canarded Radjet right?
Very well done.
I'd like to add scoops like yours for ESC&motor cooling, what did you use for that?

I'll be using 6x4s for the Dually, at least at first.
Got two of these, one pusher one tractor, but not sure they'll have the 'bite' of APC speed 6x4 so will make sure she flies with a tried and true prop before I go counter-rotating, 3 bladed.
http://www.hobbyking.com/hobbyking/s...idProduct=8091
http://www.hobbyking.com/hobbyking/s...idProduct=8090

She won't be ready for this season (this weekend will likely be the last nice weather before the big freeze hits), but glued up the main structure and man is she rigid!!!!
Also found a chunk of CF arrow in my garage from the previous owners so replaced the forward 4mm tube with this, large enough to run the left motor's throttle and left airleron's wires through it to the single RX on the right side.
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Old Oct 19, 2012, 11:12 PM
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Cool thanks Kurt, yep thats my second Radjet 800 and the scoop was just a small block of foam i had lying around.
Basicly put a hole in the radjet on an angle going down towalds the motor then covered it up with the scoop.
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Old Oct 21, 2012, 12:17 AM
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Well I found out why the 5x5 TGS was 'worse' than the APC 5x5.....

Turnigy 2826/6-2200kv (as always on this particular Radjet)
I headed out to do prop testing today. It was very windy, but the Radjet doesn't care too much about wind, though it meant GPS/Speed testing would be pretty useless. So I just went for visual for now....

3S test:
First I flew the TGS 5x5 again..... lack lustre, much like a stock Radjet....
Then an APC 6x4.... quite a bit better, but still not a rocket.
Then an APC 4.75 x 4.75.... which might have actually been an APC 5x5.... and when I threw it it just floundered to the ground!! Fly!! Fly!! DOH.... cut power at the last second - or was that one second too late?? - so the prop shredded....
Thus why I don't know what the prop truly had been..... but I think 4.75x4.75
Luckily I had many of each prop type on hand.....

So I decided to try another 4.75 x 4.75 and when I took the whole shaft adaptor, prop hub, off..... hmmmm, the prop was on BACKWARDS!!
Hey! I had been taking off the shaft adaptor and seeing it was in my hand I was putting the props on as per normal non-pusher!!! LOL
They work.. just not as good! hehe
So, let's try them ALL again.....

5x5 APC or TGS, looked equal to me.... quite fast. The motor came down "not excessivle hot" after continuous WOT flight for 4mins.
6x4 APC even faster.... and probably the best of those three tests by a visibly detectable amount. The motor a "Bit too hot" after the full flight of WOT for 4mins.
4.75x4.75..... not so great, maybe like the stock radjet (and if FLEW this time!)
The motor was warm, showing it is not being driven hard by the 'under-prop'.

Well, if 4.75x4.75 is not so good for 3S, what about 4S???

Boy did that go!!!!
A LOT faster than any of the 3S tests!! It just blistered its way around and made all the prior tests look somewhat aneamic/pathetic!
When the timer hit 4 mins I headed around to land.... and I had come off WOT every now and then, because if 3S 6x4 full wot time was marginal, the power it would be using for this speed meant it was going to get HOT!! And it went LVC just as I turned back up wind.... just cleared the treeline it was over/behind.... and landed on the oval, needing a fair walk to get to it.
But it had been the most awesome Radjet flight I had ever had!!
The motor was 'overly hot"...."ouch", umm, 50degC approx.... so I really needed a bit less continual WOT time.

When I WENT to throw it, the power level was so high - even as I tested winding it up - that I could tell I would not be able to hold and throw it! The finger holds aren't large enough to get enough grip. I use my mouth to go WOT and had planned to be 'quick' at the timing of that and giving it a throw... but I never got to!!
It just leapt off my fingers and went straight into a 45deg to 60deg climb! It as good as just launched by itself out of my hand. And for sure it could take off dead vertical (off a stand) from the ground without an issue!

But I guess this is what 4S 2836-2350kv setups do anyway!!!

So all in all....
3S 6x4 - goes very zippy/fast
4S 4.75x4.75 - blistering speed!!

I will do power tests one night this week, but it really doesn't matter too much to know (30A for the 4S?).
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Old Oct 21, 2012, 12:21 AM
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I also did numerous 'vertical until out of sight' climbs.
It turns into a spec... disappears... I wait another 1second or 2.... drop to 0% throttle and do NOTHING else. Then wait until it re-apears up there somewhere!
At worst it tumbled down into view once - the others it probably tumbled whilst out of sight - and then it just comes diving downwards.
The one tumbling time that I could see - it looked like 2 or 3 tumbles - looked a worry for that split second or so..... was it tumbing?... or going to get stuck in some aerodynamic warp?.... but no, it just resumed nose down flying out of it by iself.
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Old Oct 22, 2012, 04:12 AM
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Thanks for all the info PeterVRC
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Old Oct 22, 2012, 04:14 AM
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I'm gonna need to put some better magnets in my Radjets canopy i think...
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