Building the Guillows B-25 (26.5" span, now 31") with RC and brushless motors.

[Andy Hoffer]

Hey @Frank v B ,

Just wondering how you will get the main landing gear to retract into those tiny little holes in the nacelles?! 

Andy

[Frank v B]

re: Andy's "how you will get the main landing gear to retract into those tiny little holes in the nacelles?!  "

I'll just have the landing gear fall off after take-off and do a scale wheels-up landing.

F.

ps: trying to put retractable landing gear on this project would be absolutely insane.
Yes, I thought about it... for about a nano-second.

[Frank v B]

Tail feathers done and test assembled.  Gluing will be done after covering each item.

F.

[Frank v B]

Figured out the nose gear.

Added balsa strips to the tail end so I can sand it straight when the stabilizer is lined up.

F.

[GuyOReilly]

Looking great!
Thank you for sharing the progress of the build.

[Frank v B]

Making the second wing half (starboard).

Remember how I said "make all mistakes symmetrically".  I messed up.  Cut the trailing edge material for the wing on the plan.  I forgot the extra wingspan.


How to repair a wrong cut in balsa wood (LE, TE, spar, stringer)

Step 1- cut one side at an angle (approx 45 degrees).  The angle doesn't quite matter.  Any angle will always be stronger than a 90 degree butt joint because it has more gluing area.
Step 2- lay the cut angle over top of the remaining piece and trace the angle.  Cut the second angle. Photo 159
Step 3- pin one side in place and place a straight edge up to it, put glue on it and join it with the straight edge pushed up to it.  The joint will match exactly.  The straight edge makes sure the two pieces are straight. Let cure. Photo 160, 161.

Had to mark the spars on the ribs and cut the slots.  A pain.  Photo 158.

Frank

ps: Andy, you should be proud of teaching me about the "Macro" setting on the camera.

[Andy Hoffer]

re: Andy's "how you will get the main landing gear to retract into those tiny little holes in the nacelles?!  "

I'll just have the landing gear fall off after take-off and do a scale wheels-up landing.

F.

ps: trying to put retractable landing gear on this project would be absolutely insane.
Yes, I thought about it... for about a nano-second.

Hi @Frank v B,

Would have been a perfect fit for the builder!! 

Andy

[Andy Hoffer]

Making the second wing half (starboard).

Remember how I said "make all mistakes symmetrically".  I messed up.  Cut the trailing edge material for the wing on the plan.  I forgot the extra wingspan.


How to repair a wrong cut in balsa wood (LE, TE, spar, stringer)

Step 1- cut one side at an angle (approx 45 degrees).  The angle doesn't quite matter.  Any angle will always be stronger than a 90 degree butt joint because it has more gluing area.
Step 2- lay the cut angle over top of the remaining piece and trace the angle.  Cut the second angle. Photo 159
Step 3- pin one side in place and place a straight edge up to it, put glue on it and join it with the straight edge pushed up to it.  The joint will match exactly.  The straight edge makes sure the two pieces are straight. Let cure. Photo 160, 161.

Had to mark the spars on the ribs and cut the slots.  A pain.  Photo 158.

Frank

ps: Andy, you should be proud of teaching me about the "Macro" setting on the camera.

Hi @Frank v B ,

I am absolutely bursting with pride!  https://www.youtube.com/watch?v=MrHxhQPOO2c   

Andy

[Frank v B]

Andy,

Ah, the clips of the movie Cool Runnings.

Reminds me of the way you drive..... Sanka!.

Frank

https://www.youtube.com/watch?v=kEIfp1Uvoqc

[Frank v B]

Building the starboard wing.

Set the root rib, then the leading edge (LE), then the trailing edge (TE), then marked the tip rib by measuring.

These 4 pieces are glued together first.  Everything else slips in between.  The rubber bands at the root and tip keep pressure on the ribs while the glue sets.

Note the splice in the trailing edge.  Put it on the outboard end for the least stress.

Also note that the LE, TE  are left long on both ends.  Will trim them afterwards.

F.

[Frank v B]

Finishing the starboard wing

Photo 3163- shows the top spars in place and drying.  Also, the cockpit hatch has been glued.  Will be sanded to the shape of the fuse once the glue dries.
Photo 3164- shows the bottom spars glued in place.  The cockpit hatch has been sanded and the clear canopy temporarily set in its place... as is the nose cone.

Now back to my grand-santa chores.

F.

Lesson learned- next time it will be much better to draw the outline of the new wing on a piece of paper and then build it.  Looking at mirror images all the time confuses both of my brain cells.   The drawing would only need the leading edge, trailing edge and rib locations drawn on it in the correct location and dimension based on the first wing half.

[Michael]

That's really looking good.

[Frank v B]

Put the bones together to see what it looked like.

Still have to work at the symmetry (wheels, props, dihedral, etc.) and figure out a way to attach the wings.  The plans show the root rib butt-glued to the fuselage.  That won't work.  I will pass on the idea of removable wings and just use carbon rod(s) through the fuse to secure them.

The plane in the photo sat on its wheels but I had to put 1/2 oz of lead in the nose to make it happen.  It could be that it is tail heavy or it could be the wheels need to move back about 1/2".  Will deal with that when the plane is closer to the finish line.

Measured the span and it is 31" compared to the 26.5" as designed.  A quick calculation shows the new wing has 25.6% more wing area than the original design.  That adds up to a lower wing loading and a much more stable platform.  I will have much more control all the way to the scene of the crash.

Frank

[Andy Hoffer]

This is looking really fine. 

I love the seismic tremor in Photo 3172 !! 

Estimated power to weight ratio? 

Andy

[Frank v B]

Andy: re: your question of the power to weight ratio... Just enough!  Don't know the weight yet.

re; my earlier post " I will have much more control all the way to the scene of the crash. "    Veteran watchers of the Montreal Just for Laughs Comedy Festival, will recognize this as a paraphrase from Ron White's comedy routine (below).

Frank

https://www.youtube.com/watch?v=FH-LmkLFJg0