Frank's RV 4 30CC RV 4 by Horizon Hobbies

[Frank v B]

A re-start on this build.

Waited for the new motor mount.  The problem was the plane was designed for a Power 180 but the customer wanted a Power 360 (50CC equivalent).  The new motor mount is a 60 CC size for their XCUB 60CC.  Have to try to retrofit the firewall to accept this motor.

The new motor- Power 360 weighs 2.75 pounds, 6000 watts, can draw a continuous 130 Amps and needs a 160 amp ESC.

This plane should have unlimited vertical at idle!!

The reason for the green tape- To protect the motor from random metal pieces being sucked into the magnets.  Don't under-estimate this problem.  When building the SuperSportster the motor developed a rough spot.  It turned out a tiny piece of piano wire had attached itself to the magnets inside the motor.  Had to carefully remove it with surgical clamps.  Now the motor spins perfectly.  I then immediately taped up the large motor.

Frank

[Andy Hoffer]

A re-start on this build.

Waited for the new motor mount.  The problem was the plane was designed for a Power 180 but the customer wanted a Power 360 (50CC equivalent).  The new motor mount is a 60 CC size for their XCUB 60CC.  Have to try to retrofit the firewall to accept this motor.

The new motor- Power 360 weighs 2.75 pounds, 6000 watts, can draw a continuous 130 Amps and needs a 160 amp ESC.

This plane should have unlimited vertical at idle!!

The reason for the green tape- To protect the motor from random metal pieces being sucked into the magnets.  Don't under-estimate this problem.  When building the SuperSportster the motor developed a rough spot.  It turned out a tiny piece of piano wire had attached itself to the magnets inside the motor.  Had to carefully remove it with surgical clamps.  Now the motor spins perfectly.  I then immediately taped up the large motor.

Frank

Excellent advice!  Thanks @Frank v B !!

Andy

[sihinch]

Sorry. Stop. Hang on.

Is that a genuine compliment from Andy to Frank?

Is everything Ok? Has hell frozen?

[Frank v B]

Simon,

re: "Has hell frozen?"

Apparently.
He must be getting soft in his old age.

Frank

[Andy Hoffer]

Oh my goodness!  What have I done?  Must have been a very weak moment.

I think I will go out and clear some snow to exorcise my Dutch Demons!   

So very sorry for upsetting your equanimity!!

Andy

[Frank v B]

The new motor mount.  This was the Horizon Hobbies 60cc motor mount before customization.  The good news- the plywood is fully 3/8" thick.  The bad news:  It is reinforced inside and out with tri-stock balsa.  The grain runs lengthwise.... the way it would split. See photo 77

Adjustments:

Remember- this is a 6000 watt motor (almost 8 hp!)

1) The screws were too short.  Found longer ones  (short cap bolt one supplied with the kit and lock nut, longer bolt on the right with T nut). See photo 76
2) The hole for the wires was in the wrong place.  Had to elongate the hole with a Dremel drum sander.  See pencil marks.
3) added fibreglass cloth to the corners and brushed it with 15 minute epoxy.
4) added about a dozen wraps of epoxy soaked Kevlar (gold coloured thread).  It came from the spindle roll shown in photo 78.  It wraps around corners better than carbon.  As fine as silk as strong as steel.
5) Added carbon fibre straps.  Two on each corner.  Photo 78
6) I Added wax paper around each corner after the photo was taken to squeeze out the air and flatten everything to the plywood surface.

Let cure overnight.

[Frank v B]

Strengthened the inside of the motor box.  Used carbon straps on the inside to strengthen the tri-stock.  Wood always splits along the grain... in this case the joint.  The carbon adds strength across the tri-stock grain.  Remember, this is a huge motor.  It is exactly twice the recommended size.  Heck, why not.

The kevlar (gold coloured string) on the outside feels like steel bands.  Amazing stuff.  Glenn, enjoy your roll of it.

Note the offset on the motor.  The toughest task now is to mount it on the fuse and have the spinner come out of the centre of the cowl.

Frank

[Frank v B]

Install new motor box.  Temporarily mounted the new box with a couple of wood screws.  Attached the motor and the Cowl.  Close enough!   

Look at the difference between the plywood of the old structure and the new one (in my hand, photo  04).  The old motor mount would have blown apart at idle!

Now to permanently attach the new motor box and totally re-inforce the structure.  It seems light.

Frank

[bweaver]

The cowl makes all the difference. 

Otherwise, when I look at the second picture in the last post, I would have thought you had made a motor mount intending it to look like a wedding cake. 

It's the end result that counts.

[Frank v B]

Bruce,

You're right.  Layered motor mounts..... or..... a fibreglass cowl with tail feathers.

Frank

ps: Notice the TV in the background?

[Andy Hoffer]

The cowl makes all the difference. 

Otherwise, when I look at the second picture in the last post, I would have thought you had made a motor mount intending it to look like a wedding cake. 

It's the end result that counts.

So @bweaver ,

Which Morning Crew buffet did this come from?!! 

Andy

[Frank v B]

Hey, Andy is still alive!

Attached the new motor box to the fuselage.  Used 7 large cap screws after epoxying the wood on both surfaces.

Added a plywood brace across the top to help stop the motor from pulling down on a hard landing.
Fiberglassed the corners where the landing gear support meets the fuselage.  Photo 08
added a plywood plate to cover the large tank access hole. Photo 12

Frank

[Frank v B]

Now the tedious part installing the servos.  Installed 4 in the wing for aileron and flap.  For each one, attach a servo extension tied together with dental floss, drill 16 holes (attach servo (4), attach cover (4), drill cover (4), drill hold-down (4).  Each servo is digital, metal gear, 5.4 kg of pull (82 oz/inch or double a regular servo), connect control rods (4), install aileron horns (2) with epoxy.

Then install the fuse servos.

Frank

[Frank v B]

Attached the fin/rudder. 
Installed the servos in the fuse.  Those are standard size servos and they are absolutely lost in the fuselage.  There is enough room in there that by joining two Velcro straps, my 2 year-old grand daughter could go for a ride.
Installed the stab/elevator halves, added the tail wheel, glued in the rudder and elevator horns.  Funny to handle the stab/elevator.  The area exceeds the wing area of at least half my planes.

Frank

[piker]

Hey Frank!

I lost track.  Is this for a customer, or will you be flying it his year.

It would be a shame to give this magnificent beast away after all this work.

Robert