Toronto Electric Model Aviation Club Forum

Toronto Electric Model Aviation Club (TEMAC) => Building / Construction => Topic started by: Frank v B on February 10, 2019, 09:45:41 pm

Title: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on February 10, 2019, 09:45:41 pm
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

Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Andy Hoffer on February 11, 2019, 10:03:59 am
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
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: sihinch on February 11, 2019, 05:43:12 pm
Sorry. Stop. Hang on.

Is that a genuine compliment from Andy to Frank?

Is everything Ok? Has hell frozen?
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on February 11, 2019, 10:39:57 pm
Simon,

re: "Has hell frozen?"

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

Frank
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Andy Hoffer on February 12, 2019, 10:32:09 am
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!   8)

So very sorry for upsetting your equanimity!!

Andy

 
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on February 24, 2019, 10:07:55 pm
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.
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 03, 2019, 11:30:30 am
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
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 03, 2019, 12:12:56 pm
Install new motor box.  Temporarily mounted the new box with a couple of wood screws.  Attached the motor and the Cowl.  Close enough!   8)

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

Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: bweaver on March 03, 2019, 12:49:02 pm
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.  :P

It's the end result that counts.
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 03, 2019, 01:19:34 pm
Bruce,

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

Frank

ps: Notice the TV in the background?
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Andy Hoffer on March 03, 2019, 02:39:35 pm
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.  :P

It's the end result that counts.

So @bweaver ,

Which Morning Crew buffet did this come from?!!  :D

Andy
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 03, 2019, 05:51:51 pm
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

Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 07, 2019, 10:02:05 pm
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
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 11, 2019, 09:06:19 pm
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. :D
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. ;D

Frank
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: piker on March 12, 2019, 11:08:52 am
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
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 12, 2019, 03:15:53 pm
Piker,

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

This is for a customer.

You have it all wrong.  I get paid in store credits and I convert it to another evil project of my own.  A psychiatrist would call this conversion therapy. ;D ;D 8), my wife would call it "another bleeping airplane", my kids would see it for what it is......putting A.D.D. to good use. ;) ;)

Frank

ps: it is a really nice kit.
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 17, 2019, 09:23:27 pm
The finish line is in sight.

Added all the servos in the fuse, pushrods, assembled the canopy, added the clear bubble.  The bubble canopy had a few cracks in it so I attached it with screws, not glue.  Added the wingtip lights, the pilot, the roll bar, etc.

The only thing left are the decals and the spinner.  The spinner backplate needs to be drilled out for the huge prop shaft and add the 4 bolt holes to hold the prop.

Frank
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 21, 2019, 10:12:57 pm
Forgot about strengthening the landing gear.  The owner asked me to strengthen it because he read some reviews where it was deemed marginal.  This plane has twice the motor so strengthening we go.  The landing gear is in two halves.  Each half is bolted into the fuse with 4 bolts.

Added 3/32 ply strips to the bottom of one LG arm so it created a slot over the length.  Added 1/8" piano wire between the slot and wrapped the whole thing with Kevlar strands in 5 minute epoxy.

The neat thing about this landing gear is that it has a 3 piece sleeve made out of fibreglass that wraps over the landing gear.  All the reinforcing will be hidden from view.  Went this route because I fear the weak point in the LG is the bend where it comes down from the fuse.  The piano wire straddles this bend.  The plywood on either side of the piano wire is just to keep it in place.

Sorry about no photos.  They were taken with no camera which is all I have  (lost it, have to get a new one tomorrow.)  Am starting the second LG leg tonight.

Will retro-post* photos when I get a camera.

Frank

* pretend it is a word. ;D
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 22, 2019, 10:04:29 pm
Got a camera.  Something good came out of my lunch today with Andy "Yousuf Karsh" Hoffer.  He sent me to Henry's just down the road at Yonge and Steeles.

The first photo from my new camera.

On top- the landing gear leg with the plywood mounted on either side of the new landing gear wire.
Middle- the landing gear leg with the Kevlar wrapped around the landing gear in 4 places.
Bottom- the landing gear covers made out of fibreglass.

Frank

* The camera is a Nikon Coolpix- $119.00.  I did not tell them I knew Andy because they would probably have charged me more. ;D
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 23, 2019, 08:30:02 pm
Wrapped the LG leg with kevlar and 5 minute epoxy, wrapped it in waxed paper and stretched 2 layers of electrical tape over it to squeeze the epoxy smooth.

Removed the tape and waxed paper this morning and it was absolutely smooth.  Better than the first leg where I did not use the electrical tape.  It also soaked the kevlar better.

Frank

Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Andy Hoffer on March 23, 2019, 09:14:46 pm
Love the last photo.  Glad to see that you have mastered the art of soft focus with your new camera!!!  8)

Andy
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 23, 2019, 09:42:21 pm
Focus???   What's that??  Soft at that. ;D

You obviously have no concept of my lack on talent in specific areas. ;)

Frank
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 24, 2019, 04:33:16 pm
Almost finished,  Just a few more details to go.

I am 6'2" and feel dwarfed by this plane.

That's an 8 hp motor!!!

Frank
Title: Re: Frank's RV 4 30CC RV 4 by Horizon Hobbies
Post by: Frank v B on March 24, 2019, 08:25:02 pm
Perspective!

The new Cobra Z is smaller than the stab of the RV 4.

Frank