RC Gliders, Sailplanes and Slope Soaring Discuss rc gliders,rc sailplanes and slope soaring in this forum. Thermaling techniques, airfoils, tips, etc

Glow engine for 16' glider

Reply
Old 10-16-2012, 01:12 PM
  #1
pspring
Thread Starter
 
Join Date: Mar 2008
Location: Andover, MN
Posts: 26
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Glow engine for 16' glider

About 30 years ago my uncle gave me a 16' scratch built glider with a power pod that I have stored since then. What size motor do you think would be good? I sort of remember him saying to use a .25 but it weighs a lot more then my Kadet Jr with a .25. I don't remember the name of it but it was most likely from RCM. I could not find it in their online plans. It has a narrow wing cord and looks fast. My uncle said to make sure to dig the nose in with full down elevator when landing so it doesn't keep sliding. [X(] I know a .09 will get my paragon up ok and that's about a 10' wing. And .049 always worked good on my 6' gliders.

Thanks for any help!

Picture is posted a few posts down. Would be nice to ID it.
pspring is offline  
Reply With Quote
Old 10-16-2012, 04:18 PM
  #2
SkidMan
 
Join Date: Apr 2010
Location: Oviedo, FL
Posts: 349
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

Is there a reason you want to avoid electric?
SkidMan is offline  
Reply With Quote
Old 10-16-2012, 04:48 PM
  #3
pspring
Thread Starter
 
Join Date: Mar 2008
Location: Andover, MN
Posts: 26
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

It was origonally set up for glow. Plus, I have no electric stuff and can't afford the investment.
pspring is offline  
Reply With Quote
Old 10-18-2012, 06:36 PM
  #4
BMatthews
Moderator
 
BMatthews's Avatar
 
Join Date: Oct 2002
Location: Chilliwack, BC, CANADA
Posts: 12,275
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

Unless it's on the heavy side it's likely that a .25 would be fine. A .25 would give a nice climb for anything up to around 5 lbs. If much over that then consider upping it to a .35.

Keep in mind that there's a LOT more wing than your Kadet. Also you're looking for a climb that is like a strong uphill glide versus a steep power model angle. With the big wing it comes down to the weight to power loading. And up to around 5 lbs a .25 would be OK. If it's getting close to 6 or more then a .35.

You're also working with a power pod. Put too much power into the pod and you'll end up with thrust line issues related to the high location of the power above the true CG position. This can tend to produce a strong nose down pitching force. Given that it's best to remember that it's all about "gliding uphill" for a power pod glider.
BMatthews is offline  
Reply With Quote
Old 10-18-2012, 11:36 PM
  #5
bogbeagle
 
Join Date: Apr 2003
Location: York, UNITED KINGDOM
Posts: 1,296
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

Years ago, I had a 13-foot Kirby Kadet, which had been converted to power, and which had a sprung undercarriage. L/D of about 5, I should think. That had an old Profi .61 on the front... ample.


Based on that, I'd have thought that something in the region of a .40 would be a good choice. I mean, you do want the thing to climb at a reasonable rate, don't you?


What engines do you have?
bogbeagle is offline  
Reply With Quote
Old 10-19-2012, 05:43 AM
  #6
pspring
Thread Starter
 
Join Date: Mar 2008
Location: Andover, MN
Posts: 26
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

It weighs in at 4.5 pounds without a motor. Engines I have are .25, .29, .35 but only the .25 is R/C. The glider has a flexible throttle cable which should be nice to find the sweet spot for a nice climb out.

My brain just turned on a bit ago and told me to measure to see what size prop will fit. There is 5" from body to crank center so my guess is that a 9" prop is the biggest. So then that must mean a .25 swinging a 9" and maybe 5 pitch could be used. I probly bothered you guys for nothin.

Thanks for the info on power pod thrust effects and engine to weight. It's all helpful! I used to have a Windrifter II with a .049 para-pod which made the climb out like it was walking up steps. Looked goofy but you could keep pointed into the wind and the pod would land near you.

Maybe someone can put a name to this? I set an old .29 with a 9" prop for looks.
Attached Thumbnails
Click image for larger version

Name:	Qo39814.jpg
Views:	13
Size:	272.9 KB
ID:	1812664   Click image for larger version

Name:	Kf14392.jpg
Views:	21
Size:	253.5 KB
ID:	1812665   Click image for larger version

Name:	Dj11545.jpg
Views:	16
Size:	250.9 KB
ID:	1812666  
pspring is offline  
Reply With Quote
Old 10-19-2012, 11:52 AM
  #7
hattend
 
Join Date: Nov 2001
Location: King Salmon, AK
Posts: 2,416
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

Looks almost like a Challenger. 145" wing span (12 feet) If yours is 16 feet, might be a modified kit



[link=http://www.skybench.com/index.html?http://www.skybench.com/slnost.html]Skybench Aerotech sells the kit (scroll down to about the middle)[/link]

I used to get my 10 foot, 3.5 pound glider up with a TeeDee .049. Fly it on the wing, hook a thermal and spiral on up. Could easily speck it on a 3 minute engine run. A .25 on yours will be plenty. Used a 3 blade prop if you have clearance problems.

Don
hattend is offline  
Reply With Quote
Old 10-19-2012, 01:36 PM
  #8
bogbeagle
 
Join Date: Apr 2003
Location: York, UNITED KINGDOM
Posts: 1,296
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

Fit your biggest engine... add a little fuel... tune for full power ... launch.
bogbeagle is offline  
Reply With Quote
Old 10-19-2012, 02:20 PM
  #9
pspring
Thread Starter
 
Join Date: Mar 2008
Location: Andover, MN
Posts: 26
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

I looked at the Skybench. There's a lot of nice airships there. *drool* The Challenger is a polydihedral where mine isn't. It's possible it was taken out to make the wing tips easier to manage. There are a couple of thick metal rods in the center section that the the tips slide onto. It is also possible that it came from an enlarged plan. My uncle liked to to do that. Good idea on using a 3 blade prop if needed.

I'm working on getting the guts to just chuck it. It's feels a lot different than a Paragon in your hand. Them long wings bounce a bit. Plus I need a big area to try it out. There is a park next to a large sod field that is a canidate. Someday before winter comes...
pspring is offline  
Reply With Quote
Old 10-19-2012, 08:06 PM
  #10
OzMo
 
OzMo's Avatar
 
Join Date: Sep 2002
Location: OZark, MO
Posts: 2,692
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Glow engine for 16' glider

Hi,
the 99" Butterfly did well with .25 motor. I would sugest an OS LA 40 or 45. They weigh about the same as a ball bearinged .25 engine and are not pricey. And they are easy to run.
OzMo is offline  
Reply With Quote
Reply


Thread Tools
Search this Thread
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 06:20 PM.