RE: First Flight!!!  
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RE: First Flight!!! - 11/18/2003 2:17:06 PM   
TLH101



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Thrust HP calculatot say's 20x17 APC at ~30lbs thrust and ~129mph.

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RE: First Flight!!! - 11/18/2003 4:16:24 PM   
JoeEagle



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does the ZDZ 80 spin that fast?? i thought it was a slower reving motor....however, i don't know from experience....

zdz 80 guys, what RPM do you get on say a 26x10 or 28x10 mej/menz 2 blade

cheers

joe

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RE: First Flight!!! - 11/18/2003 4:25:19 PM   
wojtek


 

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the ZDZ 80 will hit around 8200 on those props , a 20x17 - 20x20 will spin a similar RPM ... also, you have to remember that the stationary max-rpm is loswer than that when the plane is moving ..


Wojtek

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RE: First Flight!!! - 11/19/2003 3:27:55 AM   
thehoker


 

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I heard its either the f4u or p47 thats next in line for the ARFing.
My biggest question here,people doing this and that to make a stand off sport scale plane more scale while doing the single biggest no no for achieving that look in flight.
All these huge engines that require butchering the cowls and such,wondering whats enough power,lets get back to reality here.
If your 1/5 scale p51 is doing around or over 120mph in level flight,what will that scale up to in full size(I dont know the formula but I'm guessing here),over 500 mph.I know the reno racer 51's are around there but NO WW2
P51 was ever close to that, only in a substained dive.
The real P51 wouldnt even break 400 mph untill near 16k where the supercharger starts to show its effects.
Do any of you people go to full size airshows? A 1'=1' 51 rolls a good long distance before getting light on the wheels,and climb outs are shallow,and these are modern day lightened 51's carrying less fuel and no armament like the real ones back in the days.
I go to alot of both full size and rc shows,and I can tell you that a fairly close to scale looking model flying at a realistic speed looks more scale in the air than that shinning beauty thats zipping around at 130 miles an hour.
All this talk of" is 50 ccs enough",is crazy an os 1.6 will fly it ,closer to scale speeds, save you money and weight.Look at the planes winning scale contests 25- 50 pound models flying with moki 1.8 and 2.1s, and g62's-these are 92-106" hellcats, tempests and such.
I know its not my business but that person who want to go with 80cc's in this airframe leaves me to wonder what he is thinking?Why go with this mass produced airframe to totally strip it down, reinforce it(I definetly would reinforce any airframe built for a us engines 41 cc engine to convert to a 80 cc monster) and redo it when you can get a better flying, more scale larger model.
By the way I know that us engines 41 cc is an anchore, but those speeds someone quotes of 80-90 mph are about spot on for a 51 of this size.
I had a pica 1/5 scale 51 with a moki 1.8, that plane was slightly larger,and heavier at 26 pounds, and that 1.8 still hauled it around too fast,it just didnt look right unless flying at 3/4s throttle, but there it looked great.I know excess power is nice for getting off the ground,or out of trouble, but its the wing a plane is supposed to fly on,not just the pure thrust(the ole anything will fly with enough thrust theory).
Well good luck with all of those stangs guys.

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RE: First Flight!!! - 11/19/2003 3:50:33 AM   
gary9648


 

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Well I got some high speed taxi tests on our bird, but darkness fell to quickly to get her into the air. Had her up on her mains and lifted off a couple inches and set her back down again. Tracks straight and true. Now its been nothing but rain and looks like it will be Thursday before weather clears up around here. This is driving me crazy!!!
Second plane is now about half done. Have the fuse recovered to match OLD BOY color scheme and have the invasion stripes on the wings. Hope to have the wings joined tomorrow and start on the tail wheel installation. Come on weather!!

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RE: First Flight!!! - 11/19/2003 3:56:59 AM   
wojtek


 

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quote:

My biggest question here,people doing this and that to make a stand off sport scale plane more scale while doing the single biggest no no for achieving that look in flight.
All these huge engines that require butchering the cowls and such,wondering whats enough power,lets get back to reality here.



some of us do not care as much for the scale, as much as we do for the performance .. to me the TF Mustang arf is just a cool plane that i can ****ize and turn into a high performance semiscale bird..... its just about whatever anyone is into ....

Im mostly into turbine jets and helicopters, the P51 ofers me the posibility of a big , fast prop plane that wil be easy to get flying ...


WOjtek

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RE: First Flight!!! - 11/19/2003 4:36:03 PM   
BobH


 

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While I appreciate your thoughts about speed I believe there are some misconsepctions regarding scale speed. Time, like the air we fly in cannot be scaled. No matter what size a plane is it travels through time at the same speed for any given mph. What does change is the appearence of speed. Larger objects appear to be moving slower than smaller ones. A 747 on approach looks like its barely moving when its flying at about 125 mph. Our models, because of their proximity to us appear to be flying faster than their full sized cousins when in fact they are normally flying much slower. So the best we can do is to try and create an illusion of scale flight. Slowing our plane helps with the illusion, its all smoke and mirrors!! LOL.. BobH.

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RE: First Flight!!! - 11/19/2003 5:29:44 PM   
MustangFan



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thehoker

Did these calculations when I decided on the Moki 2.10 for my TF Giant Kit now in progress.

P-51 :
Normal take off weight 10100 lbs.
take off horsepower 1490
max emergency war HP 1790

this equate to 5.65 HP per Lb. to 6.75 HP per Lb.

assuming a 22 lb. airplane., we need 3.25 to 3.9 HP to put us in the ball park.
The moki 2.1 has about 4.5 ... more than enough. But I expect my warbird to be 25lbs.
I have working inner doors ( air actuated), working rear radiator exit, full cocpit with a 1 lb. pilot from toys-r-us.

The thing I can't simulate but wish I could, is that big 4-bladed, slow turning, large pitch prop the Mustang had.
Waiting on some fellow to develope a good gear reduction unit (I can afford) that will fit within the cowl.

Oh yes ... and that sweet Merlin Engine sound !

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RE: First Flight!!! - 11/19/2003 8:29:57 PM   
Modelman



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"the P47 and the Stinson Reliant are on the ARF list for TopFlite .... "

Really!??

Craig

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RE: First Flight!!! - 11/19/2003 8:53:43 PM   
kram51



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"the P47 and the Stinson Reliant are on the ARF list for TopFlite .... "

I'm curious as to the source of this information? Neither Top Flite or Great Planes have announced either of them that I'm aware of.
That would be great, if it's true!

Mark

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RE: First Flight!!! - 11/20/2003 5:54:16 AM   
JoeEagle



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hmmm

ok, all of you really smart guys...what do you think about this article...its a little reading but interesting convo on what "Scale" speed is.

http://www.scalearo.com/maneuver_realism_speed4.htm

so back to the zdz. is it rated for 8000 plus rpm?? and since my prop was ripping on my 23x10 mej on my da 50 at 6690 rpm, how inefficient will the 22x10 prop be at over 8000?

on the zdz website it lists 8200 rpm as the top of the scale. thrust hp, admittedly not the most perfect program and i sure would like someone to point me to a better one, shows 9.22 hp with a 22x10 prop and 77 mph. sooooo

how do you figure 150 mph??

just wondering, not saying it cannot be done.

cheers

joe

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RE: First Flight!!! - 11/20/2003 8:28:09 AM   
rslstft


 

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MustangFan, keep us posted (me especially!) as to how well the Moki fits in the cowl and powers your plane. After seeing how much cutting of the cowl all the gas engines took, the Moki looked like a good alternative, and as pointed out in a earlier post, it's amazing how many planes in the 25-30lb. range you read about (such as at Top Gun, etc) that are powered by the 2.10's.

Russ

< Message edited by rslstft -- 11/20/2003 8:29:13 AM >

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RE: First Flight!!! - 11/20/2003 1:23:06 PM   
BobH


 

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Joe, I read the article by kent walters. I have read his writings before on Dynamic Scale Speed Similitude, interesting stuff. One of the problems is that the smaller planes require MORE speed to fly not less. So as a practicle matter the table might not work so well. I also think it's a difficult topic to quantify as "Preception" enters into the picture in vast amounts. You can't scale physics so we are left to art... sorta. BobH.

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