FF2017 Int. Racers: Crosby CR-4

[willsonman]

And boy, what a learning experience. So far so fun!

And we are learning WITH you! Great job, friend. Really liking how the construction is different but still simple and fun.

 

[FAI-F1D]

I know with the power setup that this plane will fly straight up. Maybe I'll launch at 70 - 80 degrees just to make the first flight last longer than 10 feet.

I wish I had that luxury. The props I'm using are pretty much stalled out until the plane gets above 30-40 mph, so I have to actually use the wings for something. Once she's up to speed everything's great, but until then it's sheer terror.

The maiden will be fun regardless of the outcome. And boy, what a learning experience. So far so fun!

Yeah, the maiden will be sheer adrenaline. Mine sure was...I was literally shaking the whole time because of the amount of concentration required just to keep everything under control. It's getting less stressful now, but man this sure isn't the type of flying I'm used to (and the irony is that I've flown stuff much faster than these racers).

 

[HilldaFlyer]

Crosby CR-4 1/6th scale

The latest progress is to cover the fuselage and put on final touches.

The fuselage formers are covered with tissue paper using Elmer’s glue to attach.

Here is the fuselage with tissue paper covering. I was in a bit of a hurry so there are wrinkles left.

Fiberglass (0.73 oz/yd) over the tissue paper. Using Kwik Kick epoxy resin.

Fully covered in fiberglass and canopy made from 2 liter bottle.

The last steps are to glue the tail to the fuselage, install a battery trough, finish servo wiring and maybe a little paint is in order.

 

[rockyboy]

That's looking pretty awesome!

 

[HilldaFlyer]

I just got done mixing up some deep blue metallic paint for the wings. Hopefully I'll be able to get the metallic white for the fuselage. It will have, at least one, glamour flight.

 

[HilldaFlyer]

Crosby CR-4 1/6th scale

Flying weight at 38.3 oz with 2200 mAh 3S pack, 6 oz over what I wanted.

 

[HilldaFlyer]

Crosby CR-4 1/6th scale

Plans are done.
View attachment Crosby CR4 6th Tube&Formers2b.pdf

If the weather holds next week... I'll try to fly.

Decals will be put on tomorrow. I want to put on headers to cover the screw holes that hold the powerpod in the fuselage. Maybe just a piece of white tape.

I went to the second hand store in search of GI Joe or Barbie Ken doll so I could mount their head in the cockpit... but I did't find any. All I found was

Buzz!
I didn't get him. However, there were lots of Barbies... maybe a female pilot is in order... just in case I fail the maiden or hit someone mid-air.

 

[PsyBorg]

Well remember you also have to judge the parking skills as well if you will use the female pilot.

 

[HilldaFlyer]

Crosby CR-4 1/6th scale

Added some decals.

Battery hatch off.

Bottom side.

Front view

Hopefully I can maiden before year end.

 

[SlingShot]

Hopefully I can maiden before year end.

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Good luck with the maiden! It looks pretty evil...but in a good way.

 

[PsyBorg]

All I can picture when I see these race planes with the really short wings is a video clip for a cartoon movie. It had an evil person controlling a Tyrannosaurus Rex. He had it going after a kid who backed into a corner and all I hear in my head is the part when he could not catch the kid.. "I have a really big head... and short stubby arms". I wish I could remember it so I could show the clip and you guys can have that imprinted on your brains too!

Edit: I know it is wayy off topic but Found it!!

 

[HilldaFlyer]

All I can think of is flying this...

Here he is with the blue wings. Maybe I should paint the cowl and turtle deck black?

Look mom.... I'm flying... falling...falling..

 

[HilldaFlyer]

Crosby CR-4 1/6th scale

Seems Penguins can fly better than the Crosby CR-4.

This is not an easy fix... I'll see if I can get another one for FliteFest 2017.
Cheers!

 

[rockyboy]

Ouch! Sorry to see the rough landing! On the positive side, the whole back of the plane looks in great shape!

Any thoughts to share about what went sideways?

 

[mrwhiskers]

Seems Penguins can fly better than the Crosby CR-4.

This is not an easy fix... I'll see if I can get another one for FliteFest 2017.
Cheers!

It appears the issue you're having is violent tip stall. With such small wings and even smaller wingtips the CR-4 seems like it would drop a wingtip at anything less than high speed. Maybe try tipping both ailerons up to create a bit of washout on the next one?

 

[HilldaFlyer]

Torque roll was pretty significant. I'm not acclimated to that kind of instability.
I'm going to try and salvage the tail of the plane... we'll see.

 

[Fidget]

Sorry to see that! I'm planning to fly the R3C this afternoon. I'm pretty afraid of that degree of instability. Kept wondering about putting a gyro in it, but thought about it long enough there isn't time now!
Cool build technique. I enjoy your other articles too.

 

[rockyboy]

Torque roll was pretty significant. I'm not acclimated to that kind of instability.
I'm going to try and salvage the tail of the plane... we'll see.

I blamed torque roll for my initial lawn dart event for the Caudron's first maiden flight too.

However, when I went out for my second flight with a rebuilt plane, I discovered the primary cause of 'torque roll' was really idiot pilot had the aileron servo directions reversed'. :black_eyed:

I did end up installing a gyro and used a 10% stabilization setting on my second flight, and while it was still a speedy handful, it was controllable, even with the gyro off after I was up in the air.

 

[HilldaFlyer]

Crosby CR-4 1/6th scale

That can be buffed out - right?

The repair will not be completed to maiden before year end, but I was able to make substantial progress on the repair.

Made a new box the same size and glued it on with Gorilla.

Fiberglass the sides with 3.14 oz cloth and epoxy resin.

Added the formers.

Installed motor mount

Added carbon fiber spar to main foam spar.

Glue the top wing panel to the bottom.

Now I just have to skin the open sections and attach the new wing. The wing needs to be reskinned with fiberglass, so that will take me into next year.

 

[HilldaFlyer]

Crosby CR-4 1/6th scale

Here goes nothing... well nothing to loose anyway.

Performed major surgery on the fuselage... enlarging wing attachment.

Here is the 1/6th scale fuselage with 1/4 scale wings. Looks more flyable to me.

Removed the paper from the wings and added a skin of fiberglass.