S.P.A.D. Aircraft - Coroplast design Discuss the growing area of S.P.A.D.S. (Simple Plastic Airplane Designs). Coroplast type aircraft, pizza box planes, etc..

Good Ground Run, No Takeoff

Reply
Old 10-18-2017, 03:02 PM
  #1
ETpilot
Thread Starter
 
Join Date: Jun 2014
Location: East Texas
Posts: 586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Good Ground Run, No Takeoff

Today was a beautiful day. Not a cloud in the sky. Temp 80*, humidity 37%, light breeze. So I cut my runway and got my airplane ready to fly. Preflight OK, engine started running good. Pointed airplane down the runway, held up elevator, tail dragger, added power all good. Ground run straight reduced the up elevator. Airplane did not seem to be gaining airspeed. Kept on the ground to end of runway. Added up elevator for takeoff and plane just stayed on ground, kicked up some dirt and came to a stop still on its gear. I was not sure what happened until I saw the engine and engine mount. The engine was pointing down.
Attached Thumbnails
Click image for larger version

Name:	image.jpeg
Views:	51
Size:	1.98 MB
ID:	2241591  
ETpilot is offline  
Reply With Quote
Old 10-18-2017, 03:07 PM
  #2
ETpilot
Thread Starter
 
Join Date: Jun 2014
Location: East Texas
Posts: 586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Upon removing the engine with engine mount and firewall, I discovered I had not epoxied the engine mount to the firewall. Only thing holding it together was 2 drywall screws. Amazing as this engine mount and firewall has had a few flights logged. The engine was powerful enough to bend the screws.

Easy fix. Drill out the screw holes and glue in hardwood dowels. Dado the firewall for the engine mount. GLUE THE MOUNT and drill and add the screws. It should work.
Attached Thumbnails
Click image for larger version

Name:	image.jpeg
Views:	50
Size:	3.70 MB
ID:	2241592  
ETpilot is offline  
Reply With Quote
Old 10-18-2017, 04:56 PM
  #3
aspeed
 
aspeed's Avatar
 
Join Date: Jul 2011
Location: Ruthven, ON, CANADA
Posts: 3,088
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Some guys use something like 3/8" or 1/2" birch ply and screw it into the bottom of the downspout. The tank may not squeeze in, and you have a hole behind the motor. I use plastic mounts, or aluminum T bar that I machine up. It takes forever to do. Your new improved way sounds ok too. I am not a fan of wood any more. It needs paint, and there is not much good paint around any more.

Last edited by aspeed; 10-18-2017 at 04:58 PM.
aspeed is offline  
Reply With Quote
Old 10-18-2017, 06:33 PM
  #4
ETpilot
Thread Starter
 
Join Date: Jun 2014
Location: East Texas
Posts: 586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Thanks aspeed. This wooden mount really works good. I just have to make sure I fabricate it right, like add glue. Lol.
Wood is easy to work with and good for a SPAD airplane. I have used plywood for my balsa models.
ETpilot is offline  
Reply With Quote
Old 10-18-2017, 07:13 PM
  #5
aspeed
 
aspeed's Avatar
 
Join Date: Jul 2011
Location: Ruthven, ON, CANADA
Posts: 3,088
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Yes, the standard maple crutch on a balsa fuselage is long forgotten too. Glass filled nylon is pretty standard.
aspeed is offline  
Reply With Quote
Old 10-19-2017, 03:56 AM
  #6
ETpilot
Thread Starter
 
Join Date: Jun 2014
Location: East Texas
Posts: 586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

What really baffles me is that there was no indication of the engine mount problem. Prior to the flight I checked the engine installation. I ran the engine idle to full power several times on the starting stand. Before takeoff one last full power run on the ground. No clue of any kind of problem. Just goes to show things can just happen. But better on the ground than in the air.
ETpilot is offline  
Reply With Quote
Old 10-19-2017, 05:33 AM
  #7
rgburrill
 
rgburrill's Avatar
 
Join Date: Dec 2010
Location: Trumbull, CT
Posts: 1,859
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

They way those screws are bent suggests you hit a hole in your runway during the takeoff roll. That would account for the mount looking good during run-up but failing on takeoff.
rgburrill is offline  
Reply With Quote
Old 10-19-2017, 02:32 PM
  #8
ETpilot
Thread Starter
 
Join Date: Jun 2014
Location: East Texas
Posts: 586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Quote:
Originally Posted by rgburrill View Post
They way those screws are bent suggests you hit a hole in your runway during the takeoff roll. That would account for the mount looking good during run-up but failing on takeoff.
Good point. That may be what happened. It took some force to bend those screws. I'll make the engine mount a bit stronger this time. I'll see if I can fine the resting spot for the airplane. Then check the runway area. Thanks
ETpilot is offline  
Reply With Quote
Old 10-20-2017, 02:55 PM
  #9
ETpilot
Thread Starter
 
Join Date: Jun 2014
Location: East Texas
Posts: 586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

I had some time to work on my engine mount. I dadoed the firewall for the engine mount. I got a nice tight fit. I checked for straight and square, all good. Then I drilled the screw holes on the engine mount and glued in the dowel. Tomorrow I will epoxy the engine mount to the firewall and add the screws. Should be stronger than before. It will be flying soon.
Attached Thumbnails
Click image for larger version

Name:	image.jpeg
Views:	11
Size:	638.7 KB
ID:	2241747  
ETpilot is offline  
Reply With Quote
Old 10-21-2017, 03:10 PM
  #10
ETpilot
Thread Starter
 
Join Date: Jun 2014
Location: East Texas
Posts: 586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default

Well, it is all back together again. I just have to set the idle and give her another try.
Attached Thumbnails
Click image for larger version

Name:	image.jpeg
Views:	28
Size:	1.39 MB
ID:	2241920  
ETpilot 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 04:48 AM.