HK / Dr.Mad Thrust Alloy 3S EDF's
Does anyone have any upgrade ideas for these units ?
They are based on :
Rotor Diameter: 50mm 5 Blade
Outer Diameter: 54.5mm
Weight: 67g with 2mm Connectors
Motor: 20mm Brushless Inrunner 4800kv
Max Amps: 18A
Max Thrust: 450g
So far I can't get near to the reported spec performance ..
18A and 450gr thrust on 3S
I get 21A and 300gr on 3S
This is worse than a stock Plastic job as I tried a 4S and it just got hot !
The twin HK Alloy set-up I have in my Concorde ... I bit the bullet in the end and plugged in 4S packs .... the model then performed much better and motors were not so hot after flight.
I am still un-impressed with these EDF's ...
Higher quality, higher power motors is about the only way to get more thrust out of an EDF.
Yes, the rated max thrust is rarely realistic for an installed EDF. You might be able to match it with a bench test using a good inlet ring and thrust tube designed to give max thrust for that fan. The best design for the inlet and outlet will rarely be the right shapes for the model, so we build something of a compromise between best fan performance and best aircraft appearance.
The fan on the plane in my avitar is in such a fan nacelle. Best inlet for thrust (sitting still on the ground) would be considerably different making the whole nacelle much larger. The fatter nacelle would present excess drag for normal flight. Once the aircraft is up to speed the inlet design doesn't need to be as wide for best performance...
Next best is my T45 on 64mm ... again pushed the battery on that but still a HK plastic EDF unit.
The 70mm's I have are garbage !
Anyway - the HK Alloy's are now flying nice as you see in the Concorde thread - BUT thrust is still way below what I get from my T45 plastic set-up ...
Trouble is - I need the alloy shrouds for when I fly without wheels ...
Is this the one you bought? http://hobbyking.com/hobbyking/store...dproduct=45263
Gooniac over on RCG swears by this on 4S. Showing over 600g thrust. I'm going to try one on my Screamer. The 10 blader , though not as efficient as the 5 blader, gives it a "swooshing" sound versus the vacuum cleaner. Whatever floats your boat I guess. I'll put it up on a wattmeter .
Folks, the challenge with the little Jpowers Skyangels is they can only accommodate a 50mm due to their fuse dia.
I do now have the Detrum 70mm and it's pretty dog gone powerful. Hobbypartz and Grayson sell a combo package for $50.00 that includes the edf, a 60 amp esc and (4 )9g servos. Pretty good deal IMO. Have that setup going into my "Flight Test" Saab Viggen.
Yep, the Detrum (Dynam) 70's are good. that's what came in the Dynam Me-262 and stock out of box these things have been clocked at 110 mph. Pretty good for an EPO scale RTF package deal.
Still not anywhere near the ideal ducting... Just can't do it and have the nacelles look scale.
There are more powerful 70mm EDF units out there... but quite a bit more expensive.
This is the 50mm Alloy I bought ...
On 3S .. it barely hits 300gr thrust.
I chose that rather than the 4S version as I suspected I might be lacking and wanted reserve voltage I could apply if necessary ... ie 4S.
This is a 50mm unit I took the rotor out of and fitted to stock Jpowers shroud ..
with this motor :
Excellent combo on 4S ....
This is the 70mm EDF unit I use ..
with this motor on 5S ....
Tried the other 70mm motors at HK and they all burnt out on 5S .. were useless on 4S.
Yes I realise that I am staying in Budget land ... given the Fleet I fly - I have to spread my finances !!
I bought the 4S version 3300kv 10 blader. Should arrive this week. Will try it in the Screamer first using a 40amp esc. Love this plane. Alot of Zipideedodah ! Going more for the "swoosh" effect than anything.
Testing Don's Wicked 4800kv 4 blader 4S setup on the bent nose Red Arrows T-45. Bungee setup. The F-18 and T-33 will remain stock Jpowers for now.
Maiden the Flight Test Viggen this weekend and re-maiden (don't ask) for the last time, my under $75.00 contest entry X47B 70mm job. I think there should be a special consolation award for the ugliest plane. I would win hands down !
The HK Mad Thrust EDF's - I can only think that serious modification is needed to get real performance out of them. The 4800kv 3S ones I have are garbage ... the only good bit being the alloy shroud.
But why oh why if it's supposed to be 50 mm .. why is it 51.x mm in reality ?
I believe that the 51mm Haoye rotor is a direct fit and less tip gap than the original.
I've got around the lack of thrust by connecting 4S to them ... but in honesty - I expect the motors to give out soon with such abuse. I don't like In-runners TBH - never had much luck with them. Every one I have had before - the shaft has shot bearings and centre magnet part.... Outrunners seem to be more robust !
Question is - what Outrunner can fit these HK alloy shrouds ?
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