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RE: (Something Fast?) Delta Build Thread - 2/18/2008 2:10:29 AM   
gooseF22


 

Posts: 637
Joined: 8/12/2006
From: Fort Wayne, IN, USA
Status: offline 		coming along.....

Hole in the back is the exhaust.

Under the cowling is a hole for intake cooling.

I may have to put a spoiler in front of exhaust....time will tell.




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< Message edited by gooseF22 -- 2/18/2008 2:26:19 AM >

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RE: (Something Fast?) Delta Build Thread - 2/18/2008 3:36:56 AM   
iron eagel



Posts: 1212
Joined: 7/15/2004
From: Middleboro, MA, USA
Status: offline 		Nice work goose!
Try a 1/16 to 1/8 inch high delta shaped dam forward of your vent. Just have it grow out of your decking in a gradual manner and it should not slow you down all that much.
I love your power setup (over a thousand watts) that ought to work very nice, sounds like it will jump into the air, as well as scream on those high speed runs. Lets see that is roughly 1 and 1/3 horsepower not bad for a little electric airplane.


Regards
Paul

< Message edited by iron eagel -- 2/18/2008 3:46:50 AM >

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RE: (Something Fast?) Delta Build Thread - 2/18/2008 2:15:32 PM   
acr007


 

Posts: 116
Joined: 12/29/2003
From: Colliers WoodLondon, UNITED KINGDOM
Status: offline 		MIke

After i lost my last delta to an rx failure in a low fast pass. I decieded to build a new version and here are some drawings so far. Having seen your latest bird i took a few bits and pieces of yours and incorporated them in mine. Hope you dont mind.

Here are a few RCCad drawings of the new Delta. It should be fast, just need to do some calculations to ensure the design is not nose heavy with engine in the front, but set back 3 to 4 inches as the wings are swept back bringing the c of g back as well.

Span 36"
Root Chord 20"
Tip Chord 6"
sweep 20"
Area 3.33ft2
AUW +- 36 to 40 ounces
oz/ft2 11 to 14

With this design the tuned pipe will extend to the rear edge of the wing thus no mess or goo all over my nice plane.

Colour scheme TBA and considering a dual rudder. The question i have always wanted to know is will a high speed delta with big control surfaces do a flat spin.....as well as go fast...

Engine MVVS Q500 and pipe with 8*8 to 8*10 prop.


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ACR007

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RE: (Something Fast?) Delta Build Thread - 2/18/2008 6:46:18 PM   
Mike Connor



Posts: 1366
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: online
quote:

ORIGINAL: acr007

MIke

After i lost my last delta to an rx failure in a low fast pass. I decieded to build a new version and here are some drawings so far. Having seen your latest bird i took a few bits and pieces of yours and incorporated them in mine. Hope you dont mind.

The question i have always wanted to know is will a high speed delta with big control surfaces do a flat spin.....as well as go fast...


Not a problem for me. Yours looks somewhere between a delta and a flying wing. looks good so far.

large control surfaces and lots of throw should put a delta into a flat spin. I think the Outlaw will do it. My delta with dual rudders would not go into a flat spin but may if I increased the throws. It would snap but a delta resist stalling and even a regular spin was more flying in circles. A knife edge was possible.


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RE: (Something Fast?) Delta Build Thread - 2/29/2008 12:59:10 AM   
gooseF22


 

Posts: 637
Joined: 8/12/2006
From: Fort Wayne, IN, USA
Status: offline 		First motor tests went well with the A123's in 6S on a 6x5.5 apc on the medusa 2500.

Mike, can you run the numbers and see what thrust and rpm you get?

The batteries will pull down to about 14 volts at this load?

I havent been able to borrow the amp meter lately. but soon.....

THe finishing touches are going on the airframe now, and it should get a cover job next week sometime. The plane is sitting at 2.5 lbs without covering. it hits 1:1 thrust at about 2/3 throttle.

we are going to light glass/CA the belly, the wingtips, and the rudder, and sweep the forward edge a little more to cut drag. The thin CA/weave is a bit lighter. more to follow.

I hope to maiden in about 3 weeks....been working alot.

We have three other delta designs that we flew last week too, a 24 inch, a 36 inch and a 48 inch. they all flew superbly. the 24 has a little hacker on it and it is about 100mph. the 36 inch has a 2200 kv three cell outrunner, and it goes about 80, and the big one has a 25 eflight outrunner with 4 cell and 12x7 prop, and it isn't too fast Yet. we are gong to upcell soon.

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RE: (Something Fast?) Delta Build Thread - 2/29/2008 1:23:46 AM   
iron eagel



Posts: 1212
Joined: 7/15/2004
From: Middleboro, MA, USA
Status: offline 		Goose sound like a winner with those A123's I love how you tucked them into the airframe. The glass CA combo ought to beef it up quite a bit for only a small amount of weight gain.
Good luck on your maiden flight.
Can't wait to hear your flight results.

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The Wrights never crashed, they only had hard landings. I 've had some hard landings myself. AMA EAA AOPA revver #185

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RE: (Something Fast?) Delta Build Thread - 2/29/2008 6:27:49 AM   
Mike Connor



Posts: 1366
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: online
quote:

ORIGINAL: gooseF22

First motor tests went well with the A123's in 6S on a 6x5.5 apc on the medusa 2500...

Mike, can you run the numbers and see what thrust and rpm you get?

....it hits 1:1 thrust at about 2/3 throttle... and sweep the forward edge a little more to cut drag. ...I hope to maiden in about 3 weeks

ThrustHP, often better for comparison then actual data, shows a 6x5.5 prop would have to turn 25,500 rpm to generate 2.5 lbs of thrust. The medusa web site calculator shows a couple of thousand rpm less would get your there. I am not that good with the electric calculations yet.

You should be able to remove up to 10% of the vertical fin area and be fine. Any more then that is untested.

Yours should be quick to cover since it does not have a raised hatch. I cover mine in half a day but that is using three colors. I can cover the bottom in one color in about 15 minutes.

Looking forward to the maiden.

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RE: (Something Fast?) Delta Build Thread - 2/29/2008 4:56:42 PM   
mmattockx


 

Posts: 2170
Joined: 4/28/2005
From: Calgary, AB, CANADA
Status: online 		Mike and others,

The best prop/power/thrust calculator going is from Pe Reivers, he has done a ton of work on prop load factors and it gives results that are often only a few % off actual testing results.

http://home.wanadoo.nl/pereivers/Goodies.html

Also a simple muffler calculation utility as well.


Mark

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RE: (Something Fast?) Delta Build Thread - 2/29/2008 7:27:23 PM   
Mike Connor



Posts: 1366
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: online
quote:

ORIGINAL: mmattockx

Mike and others,

The best prop/power/thrust calculator going is from Pe Reivers,

Mark

Thanks, That shows 21,000 rpm for 2.5 lbs of thrust.

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RE: (Something Fast?) Delta Build Thread - 3/2/2008 1:16:46 AM   
Troy-RCU



Posts: 488
Joined: 1/18/2002
From: Oceanside, CA, USA
Status: offline 		Goose, I would be leary about using a 60 amp esc and a peak amp draw of 80 amps. The issue is that when running at partial throttle you actually heat the esc up more than when at full throttle. So most guys go with the minimum esc amp rating or higher if they know they are going to be flying a lot at part-throttle. The 60amp controller may take higher bursts but it may not like to run at 60 amps part throttle for an extended period of time. It really depends on how much they understate the amp ratings. I have used a castle 125 pulling 160 amps for 60 seconds of pylon racing but I know the same controller is used in F5B where they are pulling over 200 amps and 3000+ watts (in bursts). Just make adequate arrangements for cooling.


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RE: (Something Fast?) Delta Build Thread - 3/4/2008 3:02:12 AM   
gooseF22


 

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Joined: 8/12/2006
From: Fort Wayne, IN, USA
Status: offline
quote:

ORIGINAL: Troy-RCU

Goose, I would be leary about using a 60 amp esc and a peak amp draw of 80 amps. The issue is that when running at partial throttle you actually heat the esc up more than when at full throttle. So most guys go with the minimum esc amp rating or higher if they know they are going to be flying a lot at part-throttle. The 60amp controller may take higher bursts but it may not like to run at 60 amps part throttle for an extended period of time. It really depends on how much they understate the amp ratings. I have used a castle 125 pulling 160 amps for 60 seconds of pylon racing but I know the same controller is used in F5B where they are pulling over 200 amps and 3000+ watts (in bursts). Just make adequate arrangements for cooling.


Yep, understand. it will be propped down later, and I will only be hitting it for a few seconds. more testing required. good cooling.

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RE: (Something Fast?) Delta Build Thread - 4/8/2008 3:07:56 AM   
gooseF22


 

Posts: 637
Joined: 8/12/2006
From: Fort Wayne, IN, USA
Status: offline 		Extremers!!

I have a new project going for another client that wants to go 200 mph on electric on a delta. So. the only requisite is that we use A123 batteries.

The controller can be anything and the motor must be a NEU.

OK you smart prop guys......take Mike's design and its characteristics, and drag coeff's. with more swept winglets and help me get there.....

PROJECT 200MPH A123.

I am looking for combos that would work. We can run up to 12 A123's, for 30 volts under 75-80 amp load. . Is that enough power for a little delta? If not, we can double up for 100+ if needed.

I read somewhere about a pattern plane doing 230, but I cannot find the link, it had a NeU in it if I recall.

I am thinking to put the batteries down in the wing outside the main bay, so there will be no lifted fuselage, and the motor will have a good fairing around it.

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RE: (Something Fast?) Delta Build Thread - 4/8/2008 6:36:37 AM   
Mike Connor



Posts: 1366
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: online
quote:

ORIGINAL: gooseF22


I read somewhere about a pattern plane doing 230, but I cannot find the link, it had a NeU in it if I recall.


Were you thinking about this electric Magnum?
http://www.rcuniverse.com/forum/m_5789292/anchors_5789292/mpage_1/key_magnum/anchor/tm.htm#5789292
I will leave the electric setup to the electric experts.

Getting close to a maiden on your electric Demon?

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