HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 15, 2008, 03:51 PM
Registered User
Eindhoven
Joined Jul 2007
153 Posts
microballoons vs baby powder ??

Hi Techdad,

I struggled with the imaginary weight thing as well.
Tried some samples with micro balloons etc but nothing beats a babypoweder finish! Well at least not what I tried.

Strength wise I am positively surprized by the WBPU.
With 2 filler coats, sanded and a final coat, the strength of the depron has increased so much that occasional bumping into doors, walls etc during transport hardly ever leaves a dent.
Glassing will be better but for the edges and complex shapes its difficult.


Nozzles are made out of 2 coffee cups. Expanded polystyrene cup base and thin clear cup for flexible part.
These are glued together with epoxy, then cut to size.
clear plastic is cut lengthwise to give flexible sheets. A bit like the original but mine are attached at the rear in stead .
Mounting is at the rear foam base on 2 sides. Connected with 1/16 carbon rods to motor bulkhead (vectoring)
Flexible strips of the nozzle slide into the depron exhausts (internally smooth and WBPU finished), about 1/2"over length required so they don't pop out.
Under full vector deflection it does look a bit akward...

Perhaps these pictures were posted before, lost track..

Tjarko
tjarko is offline Find More Posts by tjarko
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 15, 2008, 06:43 PM
Bob Templeton
T3chDad's Avatar
USA, AL, Huntsville
Joined Apr 2007
3,921 Posts
So baby powder is it! I just finished the final sanding. I'll get the finish coat on tonight and paint tomorrow and probably the next day...and the day after that.
T3chDad is online now Find More Posts by T3chDad
RCG Plus Member
Latest blog entry: RC Flight Log Update!
Reply With Quote
Old Aug 15, 2008, 11:21 PM
Registered User
Joined May 2008
77 Posts
hey all! just wanted to let you know, i finished my SU 37 build. I went with the full scale 2 LSPJ setup. the maiden flight was today. this thing flys so very stable! it is wonderful! however a few glitches i would like to work out... I had to add some weight to the front in order to get the CG correct. I'm using a 2200Mah 3s lipo, which is just slightly larger than suggested. has anyne else had this issue? also i could not find any 6x4 pusher props anywhere! I went with two 5.5x 4.5 apc props. am i losing a significant amount of thrust with this setup? also, is there a recomendadion for which side to put the pusher on? I know the counter rotation should cancell out anyway but just wanted to check.
Tim6806 is offline Find More Posts by Tim6806
Reply With Quote
Old Aug 16, 2008, 02:05 AM
Park Jet Guru
jetset44's Avatar
Seattle, WA
Joined Jun 2002
5,602 Posts
Tim,
Congrats on the successful maiden! Yes, it's common to have to add weight to the nose of any park jet, but especially the Su-37 with the twin motor setup due to all the weight in the back. I've got a few quarters in the nose of my Su-37, along with the TP 2100 battery.

For the props, you'll have to mail order the 6x4 pusher props since very few hobby shops carry them. I got mine from BP hobbies ( http://www.bphobbies.com/view.asp?id...5&pid=A3918191 ). Yes, you are probably losing a bit of static thrust with the 5.5" props but gaining speed, so it probably flies a little faster than the 6x4s would but doesn't have quite as good vertical performance. But if you like it that way stick with it! As long as you have comfortably more than a 1:1 thrust/weight ratio that's all the static thrust you need. The counter-rotation is nice to have, but isn't a huge deal.

Steve
jetset44 is offline Find More Posts by jetset44
Reply With Quote
Old Aug 16, 2008, 03:49 AM
Registered User
Joined May 2008
77 Posts
Thanks Steve. I'll continue with the added weight. I'll definitely order the 6x4 props because It does not feel like I have a 1:1 ratio, When I go vertical it will start to stall in 60-70 feet depending on how fast I entered the maneuver. The zero torque roll on takeoff gives me a chance to rest from fighting the torque roll on my F-22 since I loaded it with a GH Super Mega Jet and a 6x5.5
Tim6806 is offline Find More Posts by Tim6806
Reply With Quote
Old Aug 16, 2008, 12:23 PM
Registered User
MileHiFlight's Avatar
Longmont, Colorado
Joined Jun 2005
115 Posts
Tjarko - Thanks for posting the Afterburner info. Nicely done!


Everybody - What is the latest thinking on LSPJ vs Grayson Hobby's GH2212-06? I weighed a GH2212 and it came in at 54.2 gr compared to the spec 47 grams. With the GH, the SU-37 would come in 1.55 oz heavier in the tail requiring about the same additional weight in the nose. Is the overall 3+ oz of weight gain worth it?

Should I be comparing the GH to Little Screamers Park Jet or Little Screamers "Super Park Jet"?

Anyone have MotoCalc parameters for the LSPJ and GH2212-06?

-Nick
MileHiFlight is offline Find More Posts by MileHiFlight
Last edited by MileHiFlight; Aug 16, 2008 at 12:32 PM.
Reply With Quote
Old Aug 16, 2008, 12:54 PM
Registered User
Joined May 2008
77 Posts
hey, to answer, i'm a huge fan of the GH super parkjet, but its not so much the weight on this setup that would be the drawback as it would be the power consumption. the GH motor pulls 25amps with a 6X4 whereas the LSPJ pulls 16-18. in short, do you want 3 minute flights, or eight?
Tim6806 is offline Find More Posts by Tim6806
Reply With Quote
Old Aug 16, 2008, 02:03 PM
Registered User
MileHiFlight's Avatar
Longmont, Colorado
Joined Jun 2005
115 Posts
Tim6806 - Another way to look at it is flight envelope. I want to come in on the deck at high alpha and be able to punch it and have it accelerate while going straight up. I was figuring the GH ran at 23A compared to 18 on the LSPJ. That's about 27% more current and that much less flight time, not including throttle management. The other lingering thought is if I already have to add 0.5oz to the nose, and now another 1.5oz for heavy motors, what can I do to shoe horn in more battery while removing the 2.0 oz of dead weight?

JetSet44 - Steve what is the weight on the TP2100 and motors you are using? You also have 3 quarters in the nose?

Anyone else with flying motor/battery/nose weight numbers and MotoCalc numbers on the LSPJ and GH2212-06 would be appreciated.

Thanks,
-Nick
MileHiFlight is offline Find More Posts by MileHiFlight
Reply With Quote
Old Aug 16, 2008, 02:42 PM
Registered User
Joined May 2008
77 Posts
also the LSPJ motors are 2350kv vs 2200kv for the GH. If you Really want some kick, i'd say go with the 2800kv little screamers motor.
Tim6806 is offline Find More Posts by Tim6806
Reply With Quote
Old Aug 16, 2008, 05:15 PM
Registered User
Leopoldsburg, Belgium
Joined Jul 2006
222 Posts
Quote:
Originally Posted by tjarko
Hi Didier, indeed it would be good to have 2 SU's in the air.

Would you like to come to our field on tuesday evening?
This is my most convenient flying time. Childeren sleeping.
Another evening in Leopoldsburg would be OK too.
I am on vakation next week but after that should be fine.
On a Sunday is possible too.

Our field is Ornithos in Geldrop holland.
You should be able to spot it with google earth.

Tjarko
PS I like the looks without antenna !
I upgraded mine with a Multiplex RX7 IPD. no interference but big bright orange antenna..

Tjarko, i have send you a PM..

greetz
didier n is offline Find More Posts by didier n
Reply With Quote
Old Aug 16, 2008, 08:32 PM
Registered User
Joined May 2008
77 Posts
Hey, I cant seem to find any decal sheets for this... Has anyone posted or have decals for the stock color scheme?
Tim6806 is offline Find More Posts by Tim6806
Reply With Quote
Old Aug 16, 2008, 08:46 PM
Bob Templeton
T3chDad's Avatar
USA, AL, Huntsville
Joined Apr 2007
3,921 Posts
Steve posted decals much earlier in the thread. Look through the attachments starting at the beginning.
T3chDad is online now Find More Posts by T3chDad
RCG Plus Member
Latest blog entry: RC Flight Log Update!
Reply With Quote
Old Aug 16, 2008, 08:48 PM
Registered User
PhantomFlight's Avatar
United States, TX, Sherman
Joined Apr 2006
224 Posts
post #506 on page 34 (assuming the default posts per page )
PhantomFlight is offline Find More Posts by PhantomFlight
Reply With Quote
Old Aug 17, 2008, 12:48 AM
Registered User
Joined May 2008
77 Posts
Awesome Thanks guys! My SU is now complete!
Tim6806 is offline Find More Posts by Tim6806
Reply With Quote
Old Aug 17, 2008, 12:50 AM
It's a trap!
GotrekGurnisson's Avatar
Brisbane, Australia
Joined Feb 2006
3,143 Posts
Here's a direct link.
GotrekGurnisson is offline Find More Posts by GotrekGurnisson
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Super Bandit Park Jet jetset44 Pusher Prop Jet Models 1084 Jan 07, 2014 12:52 AM
Discussion SU-38 super Flanker... pps/ going e-power Insanety Pusher Prop Jet Models 2 May 02, 2008 09:47 AM
Video Sukhoi Su-37 Maiden Flight Nadim Electric Plane Talk 2 Jul 12, 2007 04:41 AM
For Sale Walkera SU-27m/SU-35 Super Flanker $100 skotbro Aircraft - Electric - Jets (FS/W) 3 Dec 06, 2006 08:42 AM
Power set up for Great Planes Sukhoi SU-31 3D Profile Park Flyer Airplane? ChrisK7 Beginner Training Area (Aircraft-Electric) 0 May 14, 2005 06:15 PM