RE: CMP BF109F BUILDING THREAD
 

Thanks Scalecraft,

I think the 85* retracts will be the ticket ! Now, what can I get rid of to raise the cash !

Yea, I agree with you about getting the forward angle right by just eyeballing pictures of the plane . You can get a good idea of how the gear should be as far as the axle being just in line with or a little forward of the leading edge of the wing . The mounting points that the plane comes with are a sure nose - over problem , don't you think ? I think the only way to avoid the problem is to do what you've done and make new mounting blocks .

Kalog, I think you hit on a good one with the thin Willliams Brothers wheels, they almost look the part too !

Dick

RE: CMP BF109F BUILDING THREAD
 

Hot Rod Todd,

They look good !

Dick

RE: CMP BF109F BUILDING THREAD
 

BobQ

Hope this is what you want. I put 1/2"x1/2" 5 ply rails.




HR Todd

I must agree with you on the field modifications. War time can make one do anything that you need to get the job done. Many field modifications gives one a lot of scale flexibility.

I do that all the time.

However, the scoops is a "G" variant factory design/trademark. But I would have put it on the Fs also if I were in North Afrikas' heat. I really don't care, it will still be impressive

Wheels, another good wheel would be the Wiliiams brothers Balloon tire also.

RE: CMP BF109F BUILDING THREAD
 

From R/C experience, the rearward position or stock location of the mains on this kit leads us to believe that there could be a nose over problem. However, I'm curious, has anyone yet built the model (CMP 109, not KMP or other manufacturer), kept the gear in the stock location and flown it? What were the actual results? Is there a nose over problem? Does it nose over only when operating from grass fields, or do hard runways also pose a problem? Anyone?

Thanks,

Peter

RE: CMP BF109F BUILDING THREAD
 

Spring Air #704 are available for ~ $127 US delivered, they include everything needed, www.retracts.com. Robart also has a set of spring down, 85 degree retracts, don't remember the price.
As to the Williams Brothers wheels, if you're going for scale position, 4" robarts are about the largest you can stuff in, and scales are 4.7"-4.8". As I recall the Williams Brothers are in the range of 4.5".
Before you commit to them, make a mockup of the wheel and see if they will fit in the well. Just remember that the wheel doesn't come straight up, but because of the forward tilt of the mechanism moves both FORWARD and UP.
So far, it's been many hours with 4" Robarts trying to get the wheel to come out of the well. Just remember to try mockup before you commit.
Bob Q.

Scalecraft'

Steve,
Many thanks, the pics are just what I needed. I have to get a contour gage.
Bob Q.

RE: CMP BF109F BUILDING THREAD
 

Hi All

Just posting to show the difference in LG position from CMP and what I did.

Also the fabrication and flight of (along with crashes) of the Yellow 14 109 is what has led me to do the LG for the CMP.

Now that I look at our small 109, I could have used even more forward rake. Oh well on the next one.

Steve

RE: CMP BF109F BUILDING THREAD
 

WillaismBros has more sizes then that, but yes if looking for scale size for the aircraft, 4.5" would be about right. With no modification to the wheel well and NOT using the plastic inserts, you can fit the 3 3/4" Vintage or Golden Age versions in there. If you use the plastic inserts, then you can only fit the 3 1/8" size.

RE: CMP BF109F BUILDING THREAD
 

Kahloq
The only way you can fit anything larger than 4" is to go into the main spar, and that is just asking for trouble. If the Williams Bro's wheels are solid the larger sizes can be turned down on a lathe. Part of the problem is that the wheels need to be thinner than the 1.15" Robarts.I could not find anything about them on their website.














'

RE: CMP BF109F BUILDING THREAD
 

The guys over at the "other" site have posted pics of the Williams Bros wheels.

Page 12, post 167:

http://www.rcgroups.com/forums/showt...896517&page=12

RE: CMP BF109F BUILDING THREAD
 

Steve,
Thanks for the pics.
I also need material type so I can obtain some: ie, stock K&S,or 6061-T6 from a supplier?
Diameter, 1/2 inch?
Thanks, Bob Q.

RE: CMP BF109F BUILDING THREAD
 

Bob

I believe the alum is 6061 solid rods from IPS, El Monte, Ca. They are remnants and sold by the pound. I would get a bit larger than 1/2" and turn it down as needed.

Since tires are being mentioned i thought I would post a pic of my 1/5.0 scale LG set up I am one day going to use on my 80" 109 G2-6. The tire/hub is a test run of a concept I tried years ago to make tires/hub ourselves.. Really hard and heavy 60 shore rubber. But we have a pretty good idea today of what should work.

Timed out will try later

Oh, before I forget, CMP is not known for getting the CG right. The diagram shows the CG a bit to far back for what I normally use for forgiving flight. Use what you know works for you in the past on warbirds.

Steve

RE: CMP BF109F BUILDING THREAD
 

I just ordered a set of 3 3/4" golden age wheels from Williams Bros. He claims he has quite a few in stock. They should be about the best set up for this plane if you want it to look a bit scale. They run about $20 + shipping. Here's a picture from the "other" site showing the williams bros. next to stock wheels.

RE: CMP BF109F BUILDING THREAD
 

Pic of the tries at a scale tire/hub/strut for a true 1/5 scale 109G that I made a few years back for my composite 80" span G version.. A bit large for this cmp model, but if I like the way this model handles, I will make a few parts for it as well.

Steve

RE: CMP BF109F BUILDING THREAD
 

Those are the tires Im using on both my KMP ME-109 and will put on this one

RE: CMP BF109F BUILDING THREAD
 

Hi Peter,

I agree with you about the nose-over problem , I'm pretty sure I'll be doing what Scalecraft is doing by installing new mounting blocks . I built a Vaillincourt FW-190 a few years back and had to reposition the gear on that , from my own fault . If you look at the pictures that are shown by Scalecraft it's pretty obvious that it should be done .

Dick

RE: CMP BF109F BUILDING THREAD
 

I used Spring Air gear and 3 3/4" Williams Bros. wheels. Will experiment with the stock rake, but may end up doing forward rake mod. Also, got an aluminum spinner from Fliteskin. Fits perfectly!

RE: CMP BF109F BUILDING THREAD
 

Spinner looks nice. That's the one they sell for their 80" BF-109? Sells for like $125?

Nose overs may not be a problem on a smooth runway, but I would guess grass could be a challenge.

Problem with angleing the gear forward is the wheels sit cocked in the wells, making it even harder to get them to tuck in. Re-modeling the gear openings and mounting points to put an backward angle on the gear when retracted allows the gear to have a forward angle when down but retract up flat.

Do the williams bros wheels tuck into the wing with a bit of room to spare?

RE: CMP BF109F BUILDING THREAD
 

Hi All

WWIIP38

Can you tell us the backplate diameter please?.

Steve

RE: CMP BF109F BUILDING THREAD
 

Steve ,
you mentioned in one of your posts that 1/2" dia .al. for the gear might not be large enough. What is the major diameter of the gear that you have shown in the pic?
Bob Q.

RE: CMP BF109F BUILDING THREAD
 

Bob

The alum rod should be .625" (5/8") .

A pic of the concept I may use to put my tire/axle on. A sleeve on the strut. Of course the set screws will be hidden. Or I could just drill the strut and avoid a sleeve.??


Note the pic of the wheel geometry near the well. The scale (+, - ) angle on the axle to the strut, along with the larger wheel is the reason why there is a hump on later versions 109 wing.

The wheel is a 3.25" williams brothers ballon tire. For a test flight, they will work.

Steve

RE: CMP BF109F BUILDING THREAD
 

Todd; Williams Bros. wheels tuck way into wells.
Steve; Aluminum spinner back plate diameter - 14.8 cm.

Dave

RE: CMP BF109F BUILDING THREAD
 

Well started the wing assembley tonight and installing the control surfaces, dam that flat paint is a pain in the a** picked up a drill to clean out the hinge holes and it was a little rusty, got crap on my fingers now its on the plane and wont come off.... even with orange oil cleaning guess it makes it an "aged plane" one thing I am trying is for glueing I use 24 hr epoxy which is VERY strong but brings in its own problems with the time taken to set, what I am trying this time as I cant just wipe off the excess is to put masking tape along each wing joint then glue it but remove the tape while the glue is still soft so it wont leave any mess, so to those who have glued their wing how did you clamp it? not alot of places to hold it tight? I think I have decided on Hobbico servos http://www3.towerhobbies.com/cgi-bin...I=L5HHV506&P=K for the rudder and elevator but for the wing servos perhaps http://www3.towerhobbies.com/cgi-bin...5&I=LXDEL9&P=K as it is single control surface for the wing on each one what do you think? advice please of course running at 6v

RE: CMP BF109F BUILDING THREAD
 

Another question is I see people talking about "nose overs" during takeoff, why not just add up elevator to control this? works on most planes I have built, and when it is rolling just reduce the elevator?

RE: CMP BF109F BUILDING THREAD
 

Hello Dave WWIIP38,

Did you use the rest of the air-retract gear that was included in the set with your new retracts? Or do you consider this no good as in terms of quality? Are your retracts air up and down, or spring down?

Further, as I'm trying to use a OS 120 AX, I/m already running in exhausts problems, becouse there is only one way to place the engine. I prefer not to stick out a huge standard muffler out od the side of the plane. Anyone already solved this?
Regards,

Eric Schumacher, Netherlands.

RE: CMP BF109F BUILDING THREAD
 

1)Steve -Scalecraft I have seen your work on RCU for quite some time , I have nothing but respect for your ability , wondering if you were ever going to start up or re-start a caffertia style shop and supply some of the great mods you do for some of the most popular ARFs ??? You know like Luke Zolner did with the H9 planes ?

2)Snaapa yes while that will work , as you know warbirds you cant hold up elevator the entire time , you will force the plane into the air too soon (or you could) this would result in possible snap and difficult to control recovery because the airlerons wont be effective at that close to the ground and with the low air speed .It will be a rudder battle to the end