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Old Aug 26, 2005, 11:30 AM
FoamyFactory.com
Tim H.'s Avatar
USA, TX, Fort Worth
Joined Nov 2001
4,343 Posts
Pusher Jet Power Set-Ups...Need For Speed!

Hey guys,

I'm REALLY feeling the need for speed again! I've been super busy with all my 3D stuff lately and have completely ignored the jet bug that's been lurking inside... I'm completely awed by the number of foamy pusher jets that have cropped up in the last year!

Anyway, I'm thinking of revisiting a couple of my older designs in Depron and am looking for input on the various power systems being used now. WAY too many threads to sift through to gleen the info...

What are the fastest set-ups being used now (motor/prop/batt.), direct drive and geared? I'm thinking 3 classes. Small - under 12oz. Med. - 16-30 oz. Large - 30 plus oz.

Below are some pics of some of my foamy pusher designs that I did about 3 years ago with Fan Fold foam. Wasn't much interest then... This was back when you couldn't even get Depron in the US. How things have changed... I'm thinking about re-visiting the MB339 and Bobcat, but with updated power systems (pusher).

I've got tons of ideas for some cool stuff... Any interest in the MB339 and/or Bobcat? I've also dug up my plans for an F-20. I'm thinking of doing it first. Don't know yet though...

Anyway, post your successfull power setups here. Hopefuly, we can turn this thread into the diffinitive "Pusher Jet Power Set-Up" thread.

Let's see whacha' got guys...

MB339 set up - Then
Mega 22/20/4
10 cell CP1700
APC 9x6 electric
VERY fast, but heavy with the CP cells.
Video of MB339 prototype

Bobcat set up - Then
MF480/Kontronic Fun-400-36
10 cell CP1700
Fast, but heavy...
Pusher set-up
Mega 16-15-3
8 cell FAU1700 NmH
4.75x4.75 prop
fast, but heavy too.

Tim H.
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Last edited by Tim H.; Aug 26, 2005 at 02:49 PM.
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Old Aug 26, 2005, 05:22 PM
Registered User
Northwest Ohio
Joined Jan 2002
2,654 Posts
Hi Tim,

Here's a kit that I am producing called the AeroCat. It's a high performance pusher "Jet" for brushless power. My current favorite power system is a Warp 4, 4 turn motor with a Thunder Power 2100 mAh 3 cell pack. I'm running an APC 6/5.5 E prop and this setup will push the AeroCat to the mid to high 60's. The vertical is simply amazing. It will just about disappear in 12 seconds.

The wing span is 32".

The Warp motors are also available in 2, 3, 5, and 6 turn versions. My buddy tried a 2 turn in the AeroCat, and we clocked it at 72 mph!!! But that is really pushing the limit for a flat foam airplane.

The AUW with that power package is 15 oz. It also slows down extremely well. It's a blast to fly and is a great diversion from 3D.

I've included a link to the video: http://modelaero.com/video/Aero5.WMV

Regards,

Scott

www.ModelAero.com
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Old Aug 27, 2005, 06:19 AM
Fly Brushless!
Hawker's Avatar
Las Vegas
Joined Aug 2002
3,136 Posts
GG,

What kind of flying time are you getting with that favorite setup of yours and the 2100 pack?
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Old Aug 27, 2005, 06:27 AM
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padge's Avatar
Yate, Bristol, UK
Joined Jun 2005
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Any chance of the plans for your MB339?
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Old Aug 27, 2005, 09:43 AM
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Northwest Ohio
Joined Jan 2002
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Hawker- I'm getting 14 to 16 minutes (approx) from the TP Gen2 2100. It's a strong pack.

Scott

www.ModelAero.com
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Old Aug 27, 2005, 09:45 AM
FoamyFactory.com
Tim H.'s Avatar
USA, TX, Fort Worth
Joined Nov 2001
4,343 Posts
Quote:
Originally Posted by padge
Any chance of the plans for your MB339?
I'm working on revising them for the smaller park flyer power setups. I'll probably do 2 versions, the original, for bigger motors, and smaller for the GWS type geared setups. I may do a little one for the smaller CD rom type motors too. I'll finish the MB339 plans after I finish the F-20 I'm working on. I'm hoping to cut the prototype parts today or tomorrow.

Scott - The AeroCat looks great! I downloaded the video a couple of weeks ago and I was quite impressed! I realy like the looks of the Bobcat types in flight. It's just got one of those "cool" planforms. I'm twisting around some ideas for something along those lines too.

Tim
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Old Aug 27, 2005, 10:11 AM
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Northwest Ohio
Joined Jan 2002
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Tim,

Thanks for the comments on the Aerocat. I didn't mean to hijack your thread.

I really like the looks of your MB339. I considered a flat foam version of that airplane. However, I am concerned about getting it to balance with a big can motor hanging off the back end. Your thoughts on that, Tim?

Regards,

Scott
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Old Aug 27, 2005, 10:46 AM
FoamyFactory.com
Tim H.'s Avatar
USA, TX, Fort Worth
Joined Nov 2001
4,343 Posts
Ballance was a bit of an issue with the Mega 22/20/4, but the big heavy CP1700 pack made ballance easy. Lipos would not have worked in the proto unless I used a big pack. Lipos will be a challange, but manageable. I'll just have to re-arrange things a bit. The smaller GWS type geqared setup and the Outrunner stuff won't be a problem on the smaller version with a 2100-2400ma 3 cell pack.

Ballance was an issue with the E-Bobcat too. I had to move the motor/fan mount aft a bit to ballance the 10 cell Sanyo 1700 Nimh pack. They were the AU "AA" sized cells so it wasn't too bad. My 3 cell Apogee 4200ma pack ballances it perfectly.

Tim
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Last edited by Tim H.; Aug 27, 2005 at 10:52 AM.
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Old Aug 27, 2005, 12:16 PM
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Bill Glover's Avatar
United Kingdom, Bracknell
Joined Nov 2000
11,483 Posts
I switched from 8x1700 AU nimhs to 3S Kokam 2000 Lipos for a decent drop in weight and increase in power. Static pitch speed is now around 115 mph (Kontronik 400-28, CAM 4.7x4.7, 25,500 rpm) while pulling only about 26A ... so duration is great.
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Old Aug 27, 2005, 12:50 PM
FoamyFactory.com
Tim H.'s Avatar
USA, TX, Fort Worth
Joined Nov 2001
4,343 Posts
Quote:
Originally Posted by Bill Glover
I switched from 8x1700 AU nimhs to 3S Kokam 2000 Lipos for a decent drop in weight and increase in power. Static pitch speed is now around 115 mph (Kontronik 400-28, CAM 4.7x4.7, 25,500 rpm) while pulling only about 26A ... so duration is great.
Sounds great Bill. Both of those planes above were done about 2-3 years ago, so lipos weren't even an option. Unfortunately, the MB339 is no longer with us... It died in the move from Kansas to Texas so I can't try the lipos. However, i need to try lipos in the E-Bobcat. It's up in the attic... I just need to yank the fan out of my F-18.

Tim
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Old Aug 27, 2005, 01:37 PM
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Bob Blackburn's Avatar
UK, Greater Manchester, Manchester
Joined Jul 2004
357 Posts
I mid mounted my motor in the EF2000

http://www.rcgroups.com/forums/showthread.php?t=394408

This allowed me to use the correct size pack for 8+ mins wot
kokham 3s 1250 (106 gramme)


It has a go brushless motor built onto a 3mm carbon prop shaft
and uses a cut down 100mm gunther prop 15 amps at 24500 on the bench
best guess is approaching 30000 rpm in a dive
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Old Aug 27, 2005, 02:09 PM
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Bill Glover's Avatar
United Kingdom, Bracknell
Joined Nov 2000
11,483 Posts
Quote:
Originally Posted by Tim H.
Both of those planes above were done about 2-3 years ago, so lipos weren't even an option.
Yup I had the 8x1700 setup in an MPX Micro Jet when they first came out in Feb. 2003. At 22.5 oz that was a real pig to solo launch - LiPos would have made a real difference. After 12 months I'd had enough and moved everything to a good old Projeti which took the weight much better, and is even nicer (and quicker!) now with the Kokams.
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Old Aug 28, 2005, 07:14 AM
Fly Brushless!
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Thanks for the info Scott.
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Old Aug 28, 2005, 05:42 PM
Bertrand MICHELS
bmaaa's Avatar
Belgium
Joined Nov 2003
1,411 Posts
Bill, in what plane you put the Kontronik 400 ??

Quote:
Originally Posted by Bill Glover
I switched from 8x1700 AU nimhs to 3S Kokam 2000 Lipos for a decent drop in weight and increase in power. Static pitch speed is now around 115 mph (Kontronik 400-28, CAM 4.7x4.7, 25,500 rpm) while pulling only about 26A ... so duration is great.

Bill, in which plane are you using this setup ?

Don't you think that the Kontronic 400, at 110 grammes, is quite on the heavy side, and that there should be motors with equivalent power in the 75 grammes range ?

The attached chart ( from http://justgofly.com/tech_450TH.htm ) is for a motor that weight only 55 grammes ! I believe that I will give it a try in my TwinJet (2 of them)

I am looking for killer set-up for booth, a MicroJet and a TwinJet.
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Old Aug 28, 2005, 06:31 PM
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Bill Glover's Avatar
United Kingdom, Bracknell
Joined Nov 2000
11,483 Posts
Quote:
Originally Posted by bmaaa
Bill, in which plane are you using this setup ?

Don't you think that the Kontronic 400, at 110 grammes, is quite on the heavy side, and that there should be motors with equivalent power in the 75 grammes range ?
As mentioned, in a Micro Jet and now a Projeti.

Yes the Kontronik is relatively heavy but (a) it's what I had and (b) it's rated for 30A continuous / 40A burst and up to 16 cells. So running at 26A on the equivalent of 10 cells it barely even gets warm
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