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Old Jul 31, 2012, 06:23 PM
UK Commercial RPAS Pilot
Scott Cuppello's Avatar
United Kingdom, England, Carlisle
Joined Mar 2007
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Just one thing......it is NOT made by FMS.....
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Old Jul 31, 2012, 06:31 PM
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lol. Need another guess.....
But it has their 'trademarks' in quality and design ideas.
Let's see... not Starmax.... Not Dynam.... not likely Freewing....
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Old Aug 01, 2012, 07:40 AM
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I have 99% finished it off. I have to take/add the pics of the final bits done.
The battery area and wiring paths, and the canopy 'antenna'/finger grab doovey to make it simple to get it off.

I did a thrust test..... by hand. It ALMOST holds itself in the air vertically.
AUW with the main, for now, 5S 3000mAH 30C battery I will use is 1180g
Thrust is 1030g
42A and 764Watts. I guess I was happy with that lowish Amp draw!
This is static and with no change to the cheaters (not cutting some of the 'bridges' out).

That is quite a way down from the bench 1.4Kg and 50Amp/840W it can do. So I would think if it can get a bit more inlet flow it should gain 0.1Kg to 0.2Kg
Then I had the brainwave (a simple one!) to test it with the hatch off !
Thrust rose to 1120g and input power increased to 43A/800W

Getting close to 1:1 and it shows that if it can get a bit more inlet flow it will gain from that - which people (and myself) really already knew anyway. But I guess it shows that even the best inlet airflow increase possible - which won't match an open hatch size - won't be helping any more than that 0.1Kg thrust gain approx.
In flight at speed it might do a bit better than these numbers above anyway.....

I am tossing up on opening up those top-side 'panel covers', to make the sprung cheater doors idea, but I don't have the bits to complete the spring hinging for now. I would have to leave them fully open all the time, which who knows if that would be good or bad..... I would actually guess it would be closer to unimportant, than to mattering. So I will toss up on that.
I am thinking to just fly it as it is, seeing it is 'flight ready' now, and then see how it flies and thus how important any more thrust really is. And seeing that all it will gain is a maximum of 0.1Kg approx, for a cost of 1A area, it might just be too much effort to bother.

There is also a chance that the ducting will be quite optimal for flight speed just as it is. So if you cut out the lower cheater holes, to get a gain from better static thrust, it could actually lose out in top speed in flight. So you gain just in the take-off/very low speed flight region, and lose at higher speeds to top speeds.
This is why a 'doors' system is better.... it works across the whole flight range. So I won't be cutting out the lower cheaters because that is a permanent non-linear curve of gain/loss across the flight speeds range.
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Old Aug 01, 2012, 08:43 AM
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Aylesbury, Buckinghamshire, Great Britain (UK)
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Originally Posted by PeterVRC View Post
Tell him to raise the nose gear length a bit. That would be better. A few degrees AoA makes a lot of difference to a plane taking off.

I bought the ARF so I could make it a hand launcher, but I would still buy ARF even if I was doing retracts because of all the other 'own choices' you can make, but also to use decent retracts. There are a lot of stories of how lousy the stock retracts are - unreliable - and I have seen a PNF in the flesh myself doing that right from new. First few cycles on the bench and one main didn't operate reliably. And almost every flight - and if down it would collapse anyway. And as mentioned, lots of people having that issue. Cheap metal trunion PZ's are fantastic ($10 ea) and it seems Durafly/FMS chose a very budget version of those to use.
It wasn't just the take-off, it pitched nose down in flight when the throttle was opened. Have to say, the stock retracts have been bullet-proof so far.

Mike
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Old Aug 01, 2012, 09:13 AM
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Hmmmm, I don;t think I have read anyone else having a pitching down under throttle use. Though with those underneath cheaters it is surely possible.
If I get that happening then I will be adding the top cheaters for sure!! They would offset that effect quite well.
The Lander F9F Panthers do that..... they have a bottom cheater and ballooning, and newer panthers - or people who modded theirs - have the hinged top doors. (I have a Panther)
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Old Aug 02, 2012, 12:33 AM
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Nice job, i have some CF coming with my vampire will use in booms and wing like u did... i know it will help prevent booms from breaking which i saw happen to a few guys planes..did u need cf in horiz stab?
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Old Aug 02, 2012, 02:26 AM
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The horizontal stab and elevator looked to be ok to me, so I didn't do anything for them.
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Old Aug 02, 2012, 07:10 AM
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Originally Posted by phoenix racing View Post
Just one thing......it is NOT made by FMS.....
HaHaha, nice one, WE know don't we, eh Scott,

tell me mate, is there a replacement EDF available to swop the out of balance & rattly vibrating motor & fan ? if so can you supply the link ?

mine seems to have too much slop in the bearings straight out of the box, even without the fan blade & spinner it still rattles ?

thanks, nice to see ur sitting on the side though Scott
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Old Aug 02, 2012, 07:55 AM
UK Commercial RPAS Pilot
Scott Cuppello's Avatar
United Kingdom, England, Carlisle
Joined Mar 2007
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Have you oiled the bearings at all?
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Old Aug 02, 2012, 02:38 PM
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What about 'oiling' the HK P40 thread ?
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Old Aug 02, 2012, 08:24 PM
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Originally Posted by PeterVRC View Post
lol. Need another guess.....
But it has their 'trademarks' in quality and design ideas.
Let's see... not Starmax.... Not Dynam.... not likely Freewing....
ah the technicalities. word on the street - fms did not design it. hk did. but the hk designed airplane is built in the fms factory........
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Old Aug 02, 2012, 08:26 PM
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Originally Posted by PeterVRC View Post
lol. Need another guess.....
But it has their 'trademarks' in quality and design ideas.
Let's see... not Starmax.... Not Dynam.... not likely Freewing....
freewing trademark is the proper hinges
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Old Aug 03, 2012, 10:34 AM
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5 coats of WBPU to the underside and 3 coats to the top..... and it is all ready to go. More on the underside to help fend off the foam rash it will pretty surely end up with!

I set it up with both Flaperons and Spoilerons, to see which method is best to slow down and shorten the long landing time it apparently has. I am pretty good at 'slowing down' fast planes, but I do see a possible issue with the Vampire seeing the booms are an exposed point to bear the brunt of high AoA landings (incoming with high AoA, or a final high AoA flare) - the tail would hit the ground first and then the boom to wing joint would eventually fracture (one day). So you would really want a "level" landing, not a high AoA one. Thus Flaperons would suit that better I would expect.

Even better would be some real flaps!! But I want to keep it a 'simple' plane.
If the landing process seen indicates that the landing speed/length is a problem then I will add them, as it would be pretty quick and easy to do anyway. An hour or two.
I sort of like the idea of having them, because this seems to be one plane actually truly worth having flaps on. Most foamies (eg P-51 etc) don't really need them at all, as they can land totally fine (slow and short enough) without them anyway.

So if I don't destroy it this weekend I will see what is worth doing during the next week. Cheater/s ? Flaps ? Move to retracts ?
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Old Aug 03, 2012, 09:41 PM
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5 coats of WBPU to the underside and 3 coats to the top
Whats WBPU? is it a brush on epoxy or something? thanks
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Old Aug 04, 2012, 02:02 AM
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Water Based PolyUrethane paint. Designed for floors, so it is a tough paint. Water based is not as tough as oil based, but it is much easier and 'cleaner' to use - seeing you just wash brushes in water.
It tends to be "self levelling" so it flows into a smooth surface, even though it was hand brushed on, I use a 25mm brush approx. and I do 'medium thick' coats (hard to tell someone what that really means! medium thick...). But anyway, you can do almost anything and not stuff it up!
By the end of numerous coats you will see it looks somewhat like a fibreglass plane - because it has made a clear shell over the plane.

Use SATIN, not gloss.

It helps a lot to make a foamie last much longer, and reduce/prevent "grass rash" - which is where the foam gets eaten away by the friction of sliding on grass/ground.
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