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Nov 06, 2005, 11:26 PM
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Hepdog's Avatar
Thread OP

EDF HydroFoamie

I've been playing around with a EDF version of the ubiquitous Hydro Foam concept. There is a short thread over in the EDF forum, but most the Hydro interest seems to be here.

At any rate, its still early days in this project, but for anyone who ever wondered what a Hydro "might" be like without the prop, this might give you an idea.

The design is based on my own thoughts (based on Micheal Connelly's idea ) and as a followup to Miss Alliance. As an EDF she flys not bad. There isn't the raw power common to this design, nor is there the complete 3D capability, but will do normal aerobatics and a pretty decent harrier. With a little more tweaking on the power set up, I think it might hover.

Bear in mind, this design was built solely to explore the EDF idea - it wasn't meant to be purty. The vids below aren't totally representative of its performance or potential either. The vids were a rush job just to prove it works...changes are already in the works. Plus getting the good stuff on tape always seems to elude me.....

Any questions fire away....

Indoors vid - way too small of a gym:

Outdoors vid - low battery and dumb thumbs but fun:
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Nov 07, 2005, 01:40 AM
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Larry3215's Avatar
Way cool hepdog!

Which fan/motor etc is that?

Is that lower center section in the water?

Nov 07, 2005, 01:44 AM
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Larry3215's Avatar

In the tree!! I love it!

The sound is cool too!

That indoor flying was gutsy! That is a tight space for one of these - especially an EDF!

Nov 07, 2005, 02:04 AM
The Big Kahuna of Foam.
bkahuna's Avatar
Originally Posted by Larry3215
Which fan/motor etc is that?
Exactly what I was wondering.
Nov 07, 2005, 08:07 AM
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Hepdog's Avatar
Thread OP
Wel the fan/motor is a bit of sticking point. I did alot of research into what would be light enough yet powerful enough to give the EDF Hydro a fighting chance of ROW. I'm completely new to EDF so it was a steep learning curve!

Bottom line is I couldn't find any units or combos that could put out enough thrust that didn't either weigh alot or need a huge battery. You can't buy this unit - you have to scratch it too. Perhaps not a realistic representation for the masses, but I only did this to see if it was even possible.

Sooo I started experimenting with what I had on hand and what I could make myself. Right now its a GWS EDF 55 shroud and a single stator CDR. The impeller is NOT an EDF impeller. A moderator raised some legitimate and serious safety issues with what I've done, so I'm not going to restart that debate.

Hopefully some manufacturer will build a EDF that is super light weight and optimized for static thrust, that's what the Hydro needs most - raw thrust. I don't think the guys over in the EDF forum are terribly interested in an EDF unit that doesn't go a bazillion miles an hour - that seems to be the quest - speed. Alot of them didn't think this was even possible. I think there is room in the market for EDF's that are more about park-flyable slower planes or even semi 3D type stuff. Maybe this will pique someone's interest - knowing that it can be done.

A EDF Hydro that performs close to what the prop version does would be a BIG seller (this season anyway ). I've got a couple more versions of the power unit to try out, hopefully before the pond becomes ice
Nov 07, 2005, 08:15 AM
Registered Plan-a-holic
Hepdog's Avatar
Thread OP
Larry the center pod doesn't touch the water. As an aside, the EDF version stays alot drier in the water, no prop blast getting everything wet

You like the tree eh? The pack was getting low, the cameraperson impatient so I couldn't wait for that "perfect" vid. I like to show reality anyway - and trees suck I almost cleared it though....
Nov 07, 2005, 08:50 AM
Kat Builder
Bobber Bob's Avatar
Hi HepDog...

I totally agree with your thoughts about units that put out "raw thrust", and am not that inclined to get in the balistic speed race either.

Having the same need for THRUST on my indoor swingwing tomcat, I used a large thrust ring on the face of my fan unit, and it increased it's static thrust by one ounce. That may not sound like a big increase, but you have to take into account that that was on a GWS 40, with a "5300" inside on a 3S 480TP.

Bob Reynolds
Nov 07, 2005, 11:11 AM
Registered User
LLoo's Avatar

your planes always amaze me. The workmanship is fantastic. How much damaged did that evil tree do? It reminds me of a maiden of mine from the spring...

I like the idea of an EDF slowflyer. I may be showing my ignorance here but couldn't you just use a larger diameter EDF to get the thrust?
Or perhaps a long shaft and two impellers in the same shroud?

Nov 07, 2005, 09:16 PM
Registered Plan-a-holic
Hepdog's Avatar
Thread OP
Thanks guys.....

I bought a lathe to try and turn better components like intake rings etc. They DO make a big difference.

A bigger fan is in the works. I tried putting more power in the smaller fan but wasn't impressed with the numbers. Basically I look at these as being the "High Bypass" equivilant for EDF's. Move lots of air slower as opposed to smaller air faster.....bigger fan more static thrust....make sense

Multiple impellers is still on the table. the little I've read about them says they aren't terribly efficient - but that "efficiency' may be a matter of context. Traditional EDF wants and needs don't line up well with this one.

Always open to suggestions
Nov 07, 2005, 10:10 PM
Registered User
Look like good videos to me!
Nov 07, 2005, 11:07 PM
Registered Plan-a-holic
Hepdog's Avatar
Thread OP

I was actually thinking about the water one - not the indoor one. A thousand apologies, the indoor one rocked, especially the not shown part where the plane went about an inch from your head and you didn't even flinch!!!!

My bad....guess I 'd better poney up on the purchases now eh
Nov 07, 2005, 11:17 PM
Suspended Account
what are your control throws? flys beautifull.
Nov 07, 2005, 11:47 PM
Registered User
I'll let it slide this time! More purchases.... you still gotta clear up you $26 glue tab!
Nov 08, 2005, 12:34 AM
Registered Plan-a-holic
Hepdog's Avatar
Thread OP
ALWAYS need more glue - especially with the tree incident

Control throws are actually very large - but with max expo. I figured that without the prop blast to aid control, I would make the control surfaces extra big and with extra travel. As it turns out, there is some form of venturi effect happening with the exhaust plume as the elevons are extremely responsive - even in a harrier. I had to go to low rates on the elevator channel first flight cause she was super twitchy + the CofG was a little rear as well. The rudders are still as much throw as I can build in as almost all directional control comes from the rudders. Ailerons are mostly for rolls only.
Nov 09, 2005, 11:00 AM
-+- PhlatBoyz -+-
kram242's Avatar
Looks like you took a part a hairdryer for the impeller, Ive experimented with the same idea a while back, to no avail.

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