RE: CMP BF109F BUILDING THREAD
 

mine did not break the back plate but did break off every screw when I removed it, I would suggest the holes are too small, I also hard mounted my motor yesterday, it does not give me a good feeling the design of the motor mount in this plane

RE: CMP BF109F BUILDING THREAD
 

snappa

My backplate broke when i tried to get the broken screw out of it!

Steve

RE: CMP BF109F BUILDING THREAD
 

I could say that sounds funny.....(you know what I mean aka "snap") but its not really....... bet we wont be the first two too get caught out might just warm the screw with a soldering iron first before removing it

RE: CMP BF109F BUILDING THREAD
 

guess I am not laughing now.... went to start my ASP on the front lawn in the plane...... motor back fired and slit the back plate in two.. and trashed the prop... not very good quality

RE: CMP BF109F BUILDING THREAD
 

I never believed from the start that the stock spinner would be usable. Using hard plastic that is suspect even for a little 2" spinner will never be reliable at over 4".

Snappa, I believe the motor mount system is not too bad, but you may want to beef it up a bit as I did.

RE: CMP BF109F BUILDING THREAD
 

HRT,

HAve you flown your plane yet?

RE: CMP BF109F BUILDING THREAD
 

No flight, I'm still finishing it up. No hurry with the weather in Iowa, it won't be flying until spring. I have made some more progress and will be posting some photos next week showing the way the gear looks on the ground, my solution to making the elevator tight, and how I opened up the air scoop to promote more cooling for the engine compartment.

RE: CMP BF109F BUILDING THREAD
 

yeah I am going to beef it up, even considering adding an alloy strip to each side of the rails to support the mount holes better as they are very close to the edge

RE: CMP BF109F BUILDING THREAD
 

This model flies or dies on monday.

Steve,

not suppose to be on the net, but had to check

RE: CMP BF109F BUILDING THREAD
 

Sent you PM

RE: CMP BF109F BUILDING THREAD
 

here is what I am doing to sort out the engine bay, I am making 2 alloy plates 85mm*20mm*2mm to space off the engine at the correct height, then two plates 85mm*20mm*5mm for the underside of the ply motor mount drilled and tapped to the size and location for the engine holes this will spread the load across the plate and provide a more secure mounting, I have noticed the ply mount has keyed supports on the bottom side at the front and back..... I guess this should be enough but I am considering some alloy angle plates drilled screwed and glued into each corner this should fix it

RE: CMP BF109F BUILDING THREAD
 

My 109 is almost complete. I just have to add the wing tip lights and do some balancing. Thought I'd post some photos showing some of the mods I made. Like others have done, I opened up the back of the cowl to promote more air flow. I also opened the little vents in the cowl to help get some inlet in an attempt to keep the crankcase a bit cooler. Here's a photo of the cowl opening. The entire front area is open, so quite a bit of air should flow through taking out some of the muffler heat.

RE: CMP BF109F BUILDING THREAD
 

Here is a photo showing the 109 next to my 1/ 5:5 scale Kawasaki Ki-61. The 109 is longer, but has a much smaller span (73" vs. 86"). Notice how tiny the rudder looks next to the Tony. The final weight came in at about 14lbs, a bit heavier than I expected. The good news is I don't have to add any nose weight, but I have to move the battery pack way back to get it balanced. It is at about 100mm with the battery at the wing mount. I might even have to add some lead in the tail.

Scale details include the two-tone spinner, yellow cowl and rudder.

RE: CMP BF109F BUILDING THREAD
 

Here's a photo showing how I mounted the gear. I used the stock rods, but added carbon fiber to the inside of the elevator pushrod. I used 4-40 rods on all ends with Hayes clevis's. I used a metal "U" to connect the elevator halves making for a very tight set up. I used the stock tank but replaced the stopper with a Sullivan heavy duty aluminum version that allows me to use large fuel tubing to the big OS 1.60. Also shown is the tail wheel mounted and a bit of detail on my rudder.

RE: CMP BF109F BUILDING THREAD
 

A couple overall views sitting on the pool table. The williams wheels look a bit thin, but they fit into the wing fine. I shimmed up the back of the retracts to add some rake to the Sierra gear. It seems like it should not be a problem with nose overs, at least if I get the CG back where it should be. Note the side view, the axles are very close to the leading edge of the wing, about as good as it gets for a warbird. I added the armor plate behind the pilot and painted some details in the cockpit. The pilot is a $5.95 plastic 1/6 scale from HobbyCity. I repainted it and added some details. Don't hold your breath waiting for a flight report since I won't be getting it into the air until next spring. That gives me some time to admire it, once I get sick of looking at it I'll be happy to get it up in the air.

RE: CMP BF109F BUILDING THREAD
 

HRTod,
How about a few pictures of the engine compartment, with the chin cowl removed, showing the mods you made for engine cooling. Also is the spinner the Platt unit and if so, did it come without holes for a prop so a 3 bladed one could be fitted?
Bob Q.

RE: CMP BF109F BUILDING THREAD
 

All I did was cut a rectangular hole in the bulkhead behind the muffler, then used some light ply to route it out the back. I opened up the little vents on the sides to prevent stagnant air (see photo).

The Platt spinner comes with no prop cut-outs, so if you want to put one of those low-performing three blade props on it, you can.

RE: CMP BF109F BUILDING THREAD
 

spinners post 564 http://www.rcgroups.com/forums/showt...8#post10958721

RE: CMP BF109F BUILDING THREAD
 

Can you remind us where we might be able to roder that spinner from?

RE: CMP BF109F BUILDING THREAD
 

As mentioned in previous posts, contact Dave Platt by phone about the spinner. His number is on his website. http://www.daveplattmodels.com/

Keep in mind that you will have to build a spinner adaptor. I used a long nut that was machined to fit in the stock lock nut.

RE: CMP BF109F BUILDING THREAD
 

Flight canceled due to fires near airfield. Road closures.

Try for 11-18-08

Steve

RE: CMP BF109F BUILDING THREAD
 

It flies or dies Tomorrow!

Good Luck!

RE: CMP BF109F BUILDING THREAD
 

HR Todd

Your model looks good!

BQ, the Platt spinner is injection molded and comes uncut.


Steve

RE: CMP BF109F BUILDING THREAD
 

Ok, flight report.

Note that although I am far from the really good pilots around, over the last 20 years I have learned to fly some of the most unforgiving scale warbirds out there. And small over weight ones mostly. And I have learned to crash over the last 20 years as well. Crashing can make you a better pilot also if you don't give up.

I say this because I don't want you guys to think its too easy and get in trouble with a really nice pre fabbed model.

I have heard that large warbird models fly way easier than small. I must say its true.

Today I flew the CMP 109 with a CMP factory wing, meaning I didn't change the LG location or put on LE slats. Like my other wing.

Specs:

Zero wind, 80 degrees, OS 108, 10% fuel 15x8 Master Airscrew prop, custom made egxhaust (I'll never learn to spell that). Model dry with non operational spring air retracts with wire struts raked forward a bit., (no tank or valve, but servo installed, maybe .25lbs less). Model dry came in at 12.25lbs. Pretty light. I figure I can put another pound on it and it will still land well. No drop tank. Too small anyway.

CGed at conservative location as shown by CMP.

Ok taxied out, plane bounced due to too much toe in. But once I'm on the runway and my engine sounds good, we're riding.

Set up in middle of runway gave a little up elevator to hold the tail down and slowly advanced throttle, stayed pretty straight as it gained speed, rocked forward a bit, held elevator as I felt it needed more airspeed, rolled out to a good speed, didn't have to fight to keep it straight, around 75% throttle it lifted, a bit nose high so I gave it a bit of down, leveled it off a few feet from the ground let it build up speed and off it went.

A bit of down trim on the elevator, a bit of left ailerone (up) and flew hands off.

Flew around for around 6 min, not a bad model. not the fastest thing in the world, but its impressive with a 108. Especially on a low pass.

To land. At around 12.25lbs, I figured I really don't need flaps or the flap variable right now. So as I approached the runway I set up nicely, at level flight, chopped the throttle and it looked like someone stopped the plane. So i gradually throttled up a bit to get air speed and it came to a speed that I felt good with so as it passed me a bit faster than I wanted, I just let it settle in, and it bounced once, slowed down, i leveled off and even after a bounce it landed as if I placed it gently on the ground by hand.

It is most forgiving and I must say that the models airframe is geometrically correct. I like it.

Now to make a really nice one.

So heres what I would advise.

1) Be calm, if your nervous taxi around till your calm, or go home.
2) Check the basics. CG, fuel, batt, servo throws and positions
3) Make sure engine runs and idles. This model has a lot of drag with the thick wing, Hstab,Vstab, spinner, ect it will stop on a dime unless you know how to slope soar and keep your air speed up to ditch safely.
4) Some crowds are waiting to see failure, go when they are not there.

One of the reasons I figure my 109 doesn't pull me off the runway is beacuse the spinner/backplate mass is so much that the rev up is slow and smooth for the 108 along with the smaller prop. So the torque of the engine is not immediate or over powering. You guys with larger engine/props may have more of a challenge to keep it straight.


Hope this helps.

I'm happy

Steve

RE: CMP BF109F BUILDING THREAD
 

Congrats Steve, nice flight report. Good to hear it flies well at 12.25 lbs since mine weighs over 14. I don't think I'll have any trouble, but I will need some flap/brake action with the higher weight and a 17X10 prop. With an OS 1.60 on the nose mine will be one fast warbird I'm sure. Not a surprise it needs some down trim. I put in a few clicks of down on every warbird for the maiden, especially those from CMP. Helps to prevent it jumping up too soon because it needs down trim.

Did you say you balanced it at 112mm, the front of the recommended zone?