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Conference vmszoo::rc

Title:Welcome To The Radio Control Conference
Notice:dir's in 11, who's who in 4, sales in 6, auctions 19
Moderator:VMSSG::FRIEDRICHS
Created:Tue Jan 13 1987
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1706
Total number of notes:27193

59.0. "MARKS/JEMCO KITS" by ROCKET::ONEILL () Thu Feb 19 1987 14:26

    I am presently building a marks jemco p51 mustang and have
    run into a few snags, mainly because of poor instruction
    (My opinion?, or is this shared) I would be interested to hear
    any comments from others who have built from one of the Marks/Jemco
    kits.                                         jim
                                                  495th
                                                  R/C squadron
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59.1Marks Models - quality?TALLIS::FISHERKay R. FisherFri Feb 20 1987 08:3915
Is this the more expensive Marks P51 with the foam sheeted wings?
I built the fun scald P51 and have seen a couple of other inexpensive
Marks models completed.  I thought the instructions with my fun scale
were awful.  I was hoping that the more expensive models were better.
The plane flew terrible.  It did not survive minor incidences.  The
strength of the nose section was weak.  All in all it was not FUN.

Please keep us posted with your results and satisfaction with Marks.

              _!_
Bye        ----O----
Kay R. Fisher / \
 
==============================================================

59.2quality?- I dont know yetROCKET::ONEILLTue Feb 24 1987 06:449
    the model in question is the fun scale kit (60 size). Witch kit
     are you refering to? The only report I have heard of delt with
    the fourty size model witch was said to have flown well until a
    tail section defect (builder error ?) caused the elevator to depart
    company. Some complaints I have with the kit include poor wood,
    vage instructions, parts under sized, parts OVER SIZED, just to
    name a few. Im about to build the fusealage (tried once, failed
    half way through due to warped wood) again and will come back with
    more comments as they arise, good or bad
59.3mark should get lifeTALLIS::LADDTue Feb 24 1987 17:5010
    i watched kay's 40 sized p51 thru construction and flew it
    several times.  to date i have to say it is the most unimpressive
    plane i have ever seen.  its worst trait was its inability to take
    any punishment.  the whole front of the fuse was just not strong
    enough, and not for a lack of epoxy.  in the air, yuk.  snap rolls
    without trying...
    
    i too was interested in some of the bigger marks models, who else
    makes a relatively cheap hellcat?
    kevin ladd
59.5GOOD VS. EVILAISVAX::JONEILLMon Jun 06 1988 09:1410
    WELL, I'TS DONE. I FINALLY FLEW THE BEAST LAST THURSDAY AND BARRING
    A BAD PULL TO THE LEFT DURRING TAXI (LEFT GEAR TOED OUT) I HAVE
    NO FURTHER COMPLAINTS (READ THAT YET) ABOUT THE PLANE. I'M NOT SURE
    WHY KAY'S PLANE ACTED THE WAY IT DID BUT MINE SEEM'S FINE. MAYBE
    THE SMALLER VERTION HAS SOMETHING TO DO WITH IT. THE PLANE TRACKS
    LIKE AN ARROW AND IS REAL SOLID IN THE AIR. IT'S BUILT REAL LIGHT
    AND THE SUPER TIGER 61... IT'S LIKE THE PLANE IS ALL ENGINE. I MUST
    ADMIT, I HATED THE KIT BUT AFTER SEEING THE END RESULT, I'M SURE
    GLAD I STUCK WITH IT.
                                                    JIM
59.6GOTTA ASK !KYOA::EVANKOMon Jun 01 1992 17:5815
  I realize that this note is somewhat old, but I have to ask.

  I recently returned to RC after several years off, and going through 
my "STUFF", I came across the 60 size Mark's fun scale Mustang I bought 
years (6 or 7) ago. 

  After reading about what people have said at the beginning of this 
note about this kit, I'm still interested in building it. But, I would 
like to know what recommedations someone can give as far as improving 
the strength of the nose section of the fuselage or any other 
modifications that need to or should be made to it.

  Any suggestions ?


59.7.60 size is bigger - and stronger!KAY::FISHERThe higher, the fewerTue Jun 02 1992 14:4718
>  After reading about what people have said at the beginning of this 
>note about this kit, I'm still interested in building it. But, I would 
>like to know what recommedations someone can give as far as improving 
>the strength of the nose section of the fuselage or any other 
>modifications that need to or should be made to it.

My negative comments about the nose strength were only about the
.40 size.  I have know reason to believe the .60 size has any
problems in this area.  Probably one of the better buys around.

Drop some notes in as you make progress on it.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
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59.8JUST THINKING FOR NOWKYOA::EVANKOThu Jun 04 1992 14:0324
  My intentions with this kit will be to modify it in several areas, 
but not in the near future. I'm still deciding on what/how and 
possibly "WHY" I want to make some of the modifications.

  I have always built kits per the instructions, and felt that it was 
about time to deviate and try something new. Modifications I am 
thinking about are;

	1. Retracts. (Have questions on wing support structure)
	2. Flaps. 
	3. Sheet the entire airframe.
	4. Glass and resin/epoxy.
	5. Paint.

  Ambitious ? Maybe. Possible ? Yes, unless someone can enlighten me 
as to why some/all of these things should not be done. My process at 
this time is to "GATHER" all the information that I can on some of these 
mod's and then decide what I want to do. The only thing that I have done to 
the kit so far was to copy the plans.

  The airframe seems to be capable of handling these modifications, 
but when I do question something, this conference helps tremendously, but I 
still have questions that will be asked in a later/appropriate topic.

59.9What about your AMA magazine?KAY::FISHERThe higher, the fewerFri Jun 05 1992 09:5817
>                                                  <<< Note 59.8 by KYOA::EVANKO >>>
>                                                     -< JUST THINKING FOR NOW >-
>
>  My intentions with this kit will be to modify it in several areas, 
>but not in the near future. I'm still deciding on what/how and 
>possibly "WHY" I want to make some of the modifications.

In this months (Jul-1992 (for sure)) and last months (I believe?) Model Aviation 
there are extensive details of modifications that Jeff Troy is doing
to his Dynaflite P-51 kit.  This months article starts on Page 52 but P-51
details don't start till much later in the article.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
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59.10STILL THINKING !KYOA::EVANKOMon Jun 08 1992 14:0947
  I have been following the article from the beginning, and that is 
what has sparked my interest in making the modifications. I felt that 
if this modifications can be made to a .40 size plane, the .60 size 
should have no problem, including retracts.

  Was looking over the plans this weekend and making notes of the 
changes that will be necessary to the airframe. So far the only radical 
change to the fuselage will be to substitute a 1/4 plywood firewall 
to accept a one piece motor mount. I plan to do away with the maple 
motor mounts supplied with the kit, but will have to see if this takes 
away from the strength of the nose section. 

  Other modifications to the fuselage are;

		1. Move tailwheel to proper location.
		2. Strip plank/sheet fuselage top.
		3. Install hard mounts for wings.

  Modifications to the wings will require a little more thought regarding 
the installation of retracts, flaps, and aileron control hardware. 

Retracts -   First and foremost, because of the grass field, and the 
 	     size/weight of the plane, I feel that 3/16ths" struts are 
	     the only viable solution. Have to consider the height of 
	     the units and associated mounting structure to ensure that 
	     they will fit within the wings. Also will have to use 
	     2.5" wheels instead of 3.0", larger wheels will not fit 
	     in between ribs without cutting into spar. (Yikes !)

	     Recently looked at some Spring Air units, and they will fit 
	     but will be tight. Need to check Rohm's and get the height 
	     of the units before I decide. Anyone have a set of Rohm's 
	     that could give me the height measurement ?

Flaps -      Will drive these from the original aileron location. Question 
	     on this, can/should the servo be moved to either side of the 
	     root rib ? The reason that I ask is since only one arm of the 
	     servo will be driving the flaps, centering (Or as close to) of 
	     the servo travel via forked linkage, differential will be kept
	     to a minimum and this makes more sense. If not, any other idea's ?

Ailerons -   Haven't decided on whether I want pushrod linkage or wing 
	     mounted servo's. Anyone have any tips pro/con ?


More issues later

59.11Retracts and grass don't mixKAY::FISHERThe higher, the fewerMon Jun 08 1992 16:1815
>Retracts -   First and foremost, because of the grass field, and the 
> 	     size/weight of the plane, I feel that 3/16ths" struts are 
>	     the only viable solution. Have to consider the height of 

Hmmmmm - can't say that I've ever seen anyone successful at retracts
on grass.  Prepare yourself for having them ripped out on every third
landing.  It can be done - but it will take the fun out of fun flys.

Hope your flying off the grass green at the local golf club :-)

Bye          --+--
Kay R. Fisher  |
---------------O---------------
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59.12SA1794::TENEROWICZTTue Jun 09 1992 07:3715
    
    Kay...
    
    	I assume this kit was designed for fixed gear.  Probably using
    landing gear blocks.  They are typically set-up to bare the load
    over four ribs.  I'd suggest that you add good 1/16 - 1/8" plywood
    doublers to each rib that will be supporting the load of the retract
    mounts.  This done they shouldn't have any more likelyhood of tearing
    out than the stock set-up.
    	You may want to add some 1/32 plywood doublers to the ribs that are
    cut out to form the wheelwell.  Also sheet the wheelwell and strut
    areas with balsa or 1/32 plywood.
    
    
    Tom
59.13STILL THINKINGPCOJCT::EVANKOTue Jun 09 1992 14:2859
Regarding -.01

           <<< APACHE::N25480$DKA100:[JEFF.NOTES$LIBRARY]RC.NOTE;1 >>>
                  -< Welcome To The Radio Control Conference >-
================================================================================
Note 59.12                      MARKS/JEMCO KITS                        12 of 12
SA1794::TENEROWICZT                                  15 lines   9-JUN-1992 06:37
--------------------------------------------------------------------------------

    Kay...

>    	I assume this kit was designed for fixed gear.  Probably using
>    landing gear blocks.  They are typically set-up to bare the load
>    over four ribs.  

	Yes it was, right, and right.

>       I'd suggest that you add good 1/16 - 1/8" plywood doublers to each 
>	rib that will be supporting the load of the retract mounts.  This 
>	done they shouldn't have any more likelihood of tearing out than 
>	the stock set-up.

	I was thinking about doing that also. The quality of the balsa 
	supplied for the ribs that will be bearing the load on the fixed gear 
	landing blocks leaves something to be desired. The wood is soft and 
	spongy. Looks like I will need to replace these anyway. Die cutting 
	for these ribs is also very poor, looks like they had verim chewing 
	them out at the factory.

	I was also toying with the ides of replacing the two ribs  that will 
	be bearing the load (mounting plate) with appropriate thickness 
	plywood to transfer/displace/disperse the stress. Don't like the idea 
	of balsa ribs as part of this support structure.

	 Good/bad idea ? 

>    	You may want to add some 1/32 plywood doublers to the ribs that are
>    cut out to form the wheelwell.  

	You betcha'.

 
>	Also sheet the wheelwell and strut areas with balsa or 1/32 plywood.

	I take it you are referring to the bottom sheeting of the wing, if so, 
	I plan to sheet the entire wing and glass.

	I have read and reread the entire "RETRACT" topic, but really didn't 
	find much in the way people are installing retracts. What I would have 
	liked to have seen was examples of how people installed their retracts 
	(support structure) and the pro's and con's of stated process. 
 
	What would have also been valuable information was to the kind of 
	surface they were flying off of, how their systems heldup, what 
	failed (If it did), what caused them to fail, what could be done to 
	improve it's integrity (If possible), and whether they would do it 
	again. 

	Guess I know where to put these questions, huh !
59.14SA1794::TENEROWICZTTue Jun 09 1992 15:1015
    
    The best structure I've see in a wood wing is to use two 3/8" square
    rails to support the retract.  these rails run threw at least four
    plywood reenforced ribs.
    
    
    "sheeting the wheelwells"  I ment the open area within the wing.  Kind
    of like making a tube that the wheel sits in that connects the top and
    bottom wing sheeting.  The wheelwell area is usually the weakest area
    and is usually in the area that sees the flight loads.  Added top and
    bottom spare within this area will also help transfer the flight loads
    outward onto the wing.
    
    
    Tom