Michel

Hi

I just finished looking at the pictures on page #8 post 180 the pictures clearly show what I m trying to show . In one picture you can see that the retract is forward , and that the cylinder is up against the rear of the port , Mike has moved the retract as far back as it can go . If the retract was positioned as the plan indicates , wouldn t there be more room for the wheel and it wouldn t hit the top and bottom sheetings

Now there another question , if I put it as the plan indicates will the plane be nose heavy on the ground . Although this may be a stupid question .

Isn t this FUN

Michel

Robinaire

My Feedback: (23)

Hi Michel. My late Irish blacksmith Grandad always said,"there is no such thing as a stupid question, if you need the answer! Under most circumstances, that little displacement would have little effect unless it was at or very close to the cg. Also, the space problem with the cyl would disappear with the more conventional type of NON-outboard strut mechanics were used. Also, it is important to determine how the CG moves, if at all, from gear up to gear down positions. The Spit is a good example of that, because the Spit wheel moves backward a substantial distance when up! Fortunately, this is not a radical thing with the P-51. Lee

Michel

Hi

Lee.................. look at page #8 post 180 center picture , it will explain what I want to show , my CG is really a later problem

Michel

Robinaire

My Feedback: (23)

Hi Michel. I looked at that pic and enlarged it. It is definitely hitting the back end of openings, if I understand the problems. I have probably missed some things, as I haven't read the whole sequence. But if I understood the problem, there is one thing that could be done. with wheel remaining centered, rotate the mechanics towards the LE. Then shim the rear mounting rails just a tad, to tilt the mechanics forward slightly. Puts a slight forward rake to the strut. I guess I'll have to read more of the msgs. I like to read peoples' comments, problems, and especially solutions, no matter what the plane, because I always learn something! Lee

Countryboy

My Feedback: (25)

Michel,

I'm trying too get a grip on what you are trying to get across here. In the picture you are descibing on page #8, it looks to me that the gear is positioned according to the plans. If you are thinking of trying to shift the gear rearward to get the tire in a thicker section of the wing, remember that for every action, there is an equal & opposite reaction. In this case, that would mean you better be carrying plenty of extra props, because it will most likely be spending a lot of time on it's nose.

Michel

Hi
On the plans if you measure from the spar to the mount of the retract on the plans , it measures 1-1/16 of an inch . In the build , the most you can do is 1-51/6 . The cylinder is at the rear of the port , you cann t move it back any more than that . But the tape measure says it all , and the fact that the picture is worth a thousand words

I have absolutely no intentions of modifying anything , but I do know how to use a measuring tape and the tape says 1-1/16 and the build says 1-5/6 , I think thats a lot to , just let slide . I also noticed that the wheel ( page #8 ) was in the correct position . So what is done is that the retract is forward and is twisted to put the wheel into position . While the plans are on my building board I checked with a string and the struts ( retracted ) are inline with each other . If I do as the build directs , they will not be in line . I m only trying to follow the plans . I do appoligze that I can not convey what I see .

Michel

Snaer810

Hi Mike,

I did get your PM also...thanks.

I did go out and measure both the plans and the actual build.

My plans inidcated 1" from the front of the spar to the back edge of the retract mount on the outboard mounting tab and 1 1/16" from the front of the spar to the back edge of the retract mount on the inboard mounting tab.

The actual build came out to 1 1/16" on the outboard mounting tab and 1 1/8" on the inboard mounting tab. So I felt a 1/16" was not that much to worry about.

My technique for this portion of the build was to leave the wing section pinned securely to the plan and center to retract by eyeballing through the axle hole to the plan and then using a straight edge to center the retract housing over the plan.

I did have to dremel out quite a bit of the cut out for the air cylinder so I could move the retract back a bit to center on the plans. You can see this on the post 180 also. Also the inboard rib from the ported rib for the cylinder also needed to be cut out slightly.

I'm not quite sure why yours would be so far off, but it might be that the cylinder cut out needs to be cut more so the retract can slide back a bit.

Hope this helps.

At times sending some close up pics with some of these problems can really help in trying to understand the problem, that way you don't have to try and explain it 3 & 4 times.....


Let us know if you figure it out or need more help.



Mike

Michel

Hi

Thanks Mike for youre reply .

I have decided to go with what the plans indicate , and put the retracts where they are marked on the plans . I will be respecting the plans to the letter . I will keep the , 1-1/8 and the 1-1/16 and use a string to keep the struts in line ( retracted ) . I m keeping the build simple and plan on building another P-51 Giant , but more in detail . Like Countryboy says , I might be spending a lot of time on my nose and breaking props . I am following the plans , so I think that I should be OK , time will tell

I will be adding some 3/32 ply to each side of the front of rib #4 and use an epoxy fiber filler to fill the empty places in the rib . The ports for the struts and the cylinder will be right in there place , and I will be respecting the plans .

Mike ............. how did the measurements go for the exhaust and the DL ?

Thanks Again

Michel

Robinaire

My Feedback: (23)

Hi Mike. It's clearer now, as I read both your and snaers comments. Because of the difference in yours and his builds, the discrepancy is probably due to "tolerance accumulation" during building. I also see that you are trying to move the mechanics BACK to reach the 1-1/16 domension. Is this the same gear specified on the plans? As I mentioned before, I have not seen these plans, and can't really talk inteligently about it.But my comments were aimed at reducing the interference in the cutouts, and NOT maintaining the 1-1/16 dim. I had said to keep the wheel where it was, and rotate the mechanics FORWARD just a tad, and make both sides the same. It would actually put the strut a tad closer to the leading edge and produce a bit more "anti-nosever" effect. I'm going to a club meeting tonight, and I'll see if anybody has that plane or plan. This is interesting to me, as whatever solution works best goes into my mental "catalog of fixes"!! Over the years, I've hit some real "doozies" of problems!! Lee

Snaer810

Hey all,

I would not look at rotating the retract mechanism forward toward the leading edge. The P51 wing and gear assembly is not like a P47 wing or F4U wing. The gear already sits quite a distance forward toward the leading edge. I believe if you move the gear assembly forward anymore your going to run out of wing because of the airfloil at the leading edge.

Mike

Robinaire

My Feedback: (23)

Very true, Mike. It would be whatever you could sneak in! I'm going to our club meeting tonight, and will see if I can find a plan! I always learn from all these things! Lee

duber3

hi Everyboddy!!

I plan to build the TF GS p-51 and I have a few questions

My first build was the TF GS corsair, it took me 1 year to build and I found that it was very hard to build, is the P51 be difficult like corsair?

second, the firewall seems to be a little thin, on my corsair I made the firewall 5/8" thick and reinforce it with 4 wood dowel, one on each side

Probably, i will start this project next winter, I will take a break for this year

thanks!!

Michel

Hi

I ve been working on my retracts . At the present position , which is dirrectly over the retracts on the plan , there is about a .040 clearance before ir will touch the top sheeting ( both of them ) . The last bit of info that I need is the toe in . Now if I understand everything from what a friend told me , its suppose to be : the line of the wheels are suppose meet at 12FT distance . I have absolutly no idea if this is right , to me it sounds like a short distance . At that distance the wheels will really be toed in , I ll be searching the web for more information on this for sure . I imagine thats its hard to get such detailed measurments .

I guess I ll only know if I m right when the model is finished . One thing is for sure , I followed the plans . The retracts are dirrectly over the retracts of the plans , its got to count for something . I didn t change the angle of the rails , they are in the same place TopFlite put them . I m still unsure though . those are big wheels

Michel

aghost

My Feedback: (13)

Michel: The 12FT distance seems to be too much toe in. I think thats about 4 -5 degrees on each wheel.

I had (ouch, past tense, it still hurts) the kit and now just finishing up the ARC. The mains should have something between 0 - 1 degee of toe in. I just lay 36" yardsticks against the installed wheels then stand back and look at it. If it looks straight or just has a slight toe in, its OK. The yardstick makes a toe in/out much more obvious.

Brian

doublebs

hello everyone . damn snow!! cleaned up outside most of the weekend . nothing new to report as far as progress goes . much like you mike the garage is getting cold now . gonna have to crank the heat to get anything done out there .

brian.......do tell us about your boo boo . that is if its not too painful for ya . plane ? pilot ? both ? ....................

berrick

aghost

My Feedback: (13)

I bought my TF P-51 GS from a club member who only builds so I did not have a year or two of building time invested in the plane. So not as painful as it might have been.

Last winter (2006-2007) I replaced the radio receiver, on/off switch, flight battery, and the flap servos. Flew the plane a few times during the late winter, early spring as the weather permitted. Then it happened at a fun fly in a nearby town on flight #30. Did the range check thing with the engine running. OK. Took off easily, then about 20 ft up, the nose dropped down slightly, and my plane pancaked right into the ground. The center of the wing was crushed and a horizontal stabilizer was torn off. Engine, receiver, and most of the servos are OK.

Definitely some type of radio interference. There was only one other fellow on my frequency at the funfly, but a radio impound was in operation so it wasn't his. Could have been RF noise from the plane or some outside source. The fellow on the same frequency was hit once the next day in the same area of the field. However we both flew other planes on that same frequency both days without any hit.

I bought the 6 channel Futaba 2.4G radio the next week. I did not plan to go to 2.4G since I had a couple of relatively new Futaba radios. However, after that crash, a couple hundred dollars for a more RF immune radio seemed like a smart thing to do. I ran three 2.4G receivers in five planes over this past season. Really good secure link. I just bought the Futaba 7C 2.4G radio.

A picture of the downed plane is attached.

Brian

Robinaire

My Feedback: (23)

Hi Mike. a toein of 1 deg is sufficient. Thats per leg, so if the total between the wheels is 2-3 degs, it should be perfect. Excess toein can be just as bad as toeOUT, which is an absolute NO-NO-! A few years back, I watched a guy stand his plane on its nose 3 times in a row on take off. It was a hard-top runway, and when we took a look at it, he had about 12-14 degs between the 2 wheels! The high friction simply put the brakes on!! Lee

Michel

Hi

Thanks for the help on the toe in . It makes a hec of a lot more sense than what I ve come up with . . To-morrow I will be finishing off my retracts . And start preparations for the sheeting . To me this is a challenge , I don t want to use a lot of weights to hold down the sheeting . I believe that its not a good idea , it will deform the wing


Michel

upton

Michel

I am ready to skin the bottom of my wing.

I plan on CAing the leading edge then I think wood glue and masking tape might work well.
Maybe a light weight here and there to make sure everything is contacting.

Joining the wing went fairly smooth. After 3 or 4 trial fits! I never seem to have enough clamps.

Brian

Michel

Hi

Same here , never have enough clamps or the right ones . So I ve decided to start a collection Putting the wings to-gether was fairly easy . I plan on useing the same procedure as you , I might use some magazines to make sure the sheeting is to the ribs . I was told after the wing is done its all down hill , so far I d say that its going well

I ll only be getting to the fus in Febuary or so , I m also building a TopFlite P-47 Giant . I ll be starting with he tail feathers and the fus on that one

We ve had about 60cm of snow here in northern Quebec , rather have snow than rain . I work at a ski hill so the bosses are happy

Michel

Snaer810

HI Guys,

Just an idea on sheeting your wings if you havn't already started. I used CA on the leading edge and Gorrilla Glue to bond the sheeting to the rest of the structure. Once laying the sheeting down I used 1 gal. plastic storage bags filled with play sand. It worked out perfect. I was able to use 4 bags and they covered one wing half at a time, evenly spreading the load over a larger area and forming to the wing airfoil. The Gorrilla Glue expands filling in gaps very nicely and made a very strong bond. I was not concerned with wieght on the wing sense it was distributed pretty evenly. Make sure you leave the wing tabs and center supports on when sheeting the bottom. I have constructed a few small braces to fit the bottom of the wing to sit in when it comes time to sheet the top.

Important: If your planning on installing doors etc., DO NOT sheet the top of the wing yet until the door installation is complete.

Have fun guys.....We need to see some pics though.....


Mike

Michel

Hi Mike

Thanks a lot for the construction tips on sheeting . You can be sure that it will come in handy . I will be syarting to sheeting the wings very shortly . And I think that I will use Gorrilla glue

Michel

upton

Michel

If you havent started skinning your wing yet take a look at this thread.

http://www.rcuniverse.com/forum/fb.asp?m=6747681

I know they are talking about the ARF version, but I did the same thing with the shear web in the gear area.


Brian

Snaer810

Hey all,

Looks like Brian beat me to it. This thread [link]http://www.rcuniverse.com/forum/fb.asp?m=6747404[/link] on the ARF is very helpful. I know they already advise us to make sure the Shear Webs are glued in cross grain, but the use of the ply would definitly be a big help so the wing does not twist in the gear area which is taking most of the stress.

GREAT IDEA!!!


Mike

Michel

Hi
It sure does make a lot of sense , doesn t it . My shear web has already been installed , the right way . But I think that what I m going to do is add some fiberglass and resin . I will deffinatly add some reinforcement to this area . What the hec do I have to lose . I ve already added some hardwood triangular stock the the corners of ribs #4 and #5 and both sides of the spars , 8 in all . Glued to the spars and the ribs

Thanks Guys

Michel