never put this much weight in teh nose before
 

Finally have the Royal Bearcat finished and ready fly. To balance the plane I’ll need 1 lb, 11.8 oz. in the nose – which is way more than I’ve ever done. My question is where/how to do this.

Option 1 – bolt weights on the sides of the engine mount as shown (pic 1)

Option 2 – bolt/epoxy weight to the plank and frame cowl (pic 2)

Option 3 – buy a bunch of those Great Planes sticky lead weights and place them in several locations

This plane was originally 95% built in 1991 by an unknown person. It seems to be well made, but that’s a long time and a lot of weight – I’m worried about the plane shaking apart. Maybe this is why it’s never been flown before?

RE: never put this much weight in teh nose before
 

Holy Cow, 1.75 lbs of lead...  that's a lot of extra weight to carry!

Can you put a larger engine in it to compensate a bit..  I would much rather have more engine, than more dead weight, that a smaller engine would have to lug around!!  Put your battery packs, servos, etc.  as far forward as possible

Although baised upon the Pictures, I think the best way would be to bolt some weights on the side of the engine mount!

Just My two cents worth!

Craig.

RE: never put this much weight in teh nose before
 

No other engines, final weight is about 9 lbs. I'm looking at beefing up the cowl to put the weight as far in front as possible. I already have the battery in front of the CG - I'll try moving that as well.

RE: never put this much weight in teh nose before
 

can you move the engine forward on the mount?
can you move the servos forward?
so much weight is no joke for the LG as well.

RE: never put this much weight in teh nose before
 

I think I'll move the engine tonight - might be able to get a full inch. Will having the prop sticking out that extra inch make any new problems?

RE: never put this much weight in teh nose before
 

Looks like you may even have room to mount your battery pack on the
side of or underneath the engine mount, tie-wrap it to the mount. Wrap
the battery in a small plastic baggie to keep the fuel off of it. If at all
possible don't fasten lead to the cowl.

RE: never put this much weight in teh nose before
 

Here is one way to get 4 ounces as far forward as possible:
http://www.harryhigley.com/EngineAccessories1.htm


Tom

RE: never put this much weight in teh nose before
 

How about 3 pounds of lead in the nose. Any plane that was designed with one of those round engines up front have a short coupling if they are scale. These were very heavy engines so the nose moments reflect that so the full scales could get a CG. I used a 6 volt sub C battery mounted right behind the fire wall, moved everything I could all the way forward then had to use epoxy and shot shell lead in the nose ring to get this plane to CG. At one point i removed the four stroke and installed a 2.4 gas engine with EI and still needed lead. Today when I'm building any of these planes I cheat and extend the fuse and fire wall until I find the CG location. Not true scale but it makes for a better flying plane.

RE: never put this much weight in teh nose before
 

NEVER put a 2 stroke in a plane like that!

Jus sayin.

RE: never put this much weight in teh nose before
 

Screw the weights to the engine mount. DO NOT put them in the cowl. The cowl was not designed to hold weight, so it will probably break, fall off, or both

RE: never put this much weight in teh nose before
 

Well I wanted to do this the easy way, replace hinges, tighten this and that - get it to the field on Sunday with minimal expense (bought it with the two stroke installed). However, I’m now replacing the fuel tank, making a mount for the battery under the engine and moving the engine forward a full inch. Darn, I already paid $115 for the plane and engine – now more expense, what next? I expect to cut the nose weight in half.

RE: never put this much weight in teh nose before
 

A Sub -C battery is worth a lot of weigtht up front. It's one of the reasons you don't see a lot of them in normal use. I still have a couple of them in 6 volt, not in use at the moment but you never know.;)

RE: never put this much weight in teh nose before
 

Two hundred percent agreement on this. I usethe longest socket head cap screw I can find for mounting the engine, making sure it doesn't run out of threads when tightening the engine down. What sticks below the mounts makes great mount forweights. I've used things like a 3/4" conduit strap and modified the curve to fit the bolt pattern, then poured a block of lead around the conduit strap. Idid one with 9 oz. You could use two of these a little weights one on front motor screws and one on the back ones. For just an oz or so, I just use a piece of sheet lead and some washers. Always use some thread lock as you can't really tighten lead sheeting down with screws as it will continue to deform and loosen up.

Don

RE: never put this much weight in teh nose before
 

I suggest that you also look to see if the tail end can be lightened. Every oz saved in the tail translates to several ozs in the nose, especially in a short nosed plane.

RE: never put this much weight in teh nose before
 

Agreed-don't put them on the cowl. And the Higley heavy hub will definitely help out.

RE: never put this much weight in teh nose before
 

Nine pounds is not even a little bit heavy for this airplane and it will fly just fine at that weight. I usually build a weight box that mounts to the firewall and/or engine mount. I rarely put my weight in the cowl itself unless it is a minimal amount and the cowl mounting system is very rugged.

RE: never put this much weight in teh nose before
 

Scratchie
My Royal Sterman needed almost 2lbs in the nose even with the ys120 and a big battery,,it flew fine.

My Kingfisher which is about the same size and wing area as that Bearcat weighs almost 16lbs and flies awesome but it's not for a beginner

Welcome to the world of scale aircraft, keep the speed up on takeoff/landing ;)

RE: never put this much weight in teh nose before
 

Sratchie..

I just remembered that one of the modelers at my field has a Beech staggerwing that he had to put quite a bit of lead up front, and this is what he did..

he took his spinner (Aluminum, of course) roughened up the inside of the spinner with very course sand paper, placed the spinner on his bench  vice, placed nose down, used a level to get it level in all directions then poured melted lead in the spinner since he had it completely level in all directions, it basically self balanced.  you cant get the weight any farther forward than that!!

Craig. <br type="_moz"/>

RE: never put this much weight in teh nose before
 

No offense but this is a bad idea for a multitude of reasons.

RE: never put this much weight in teh nose before
 

Hi!
Yeah!
A very bad idea!

It's an easy fix to lighten the plane
Grab that Dremel tool of yours and carve away all the wood you can at the rear...there is lots of it! (I have the Marutaka Bearcat kit myself). Plywood ribs in the fuselage don't have to be wider than 0,5cm and all those balsa block could be hollowed.
Then mount the tank and battery beside the engine under the cowl. It's no good having the engine sit vertical...you will probably have tank problems if you do. Mount it sideways! Much better. Use a 350-400cc tank and two clunks (Uni-flow sytem for best fuel delivery)
Also move the servos as far forward you can! Use 3mm plywood mounts made your self with a Dremel and 3mm carbide router bits!

RE: never put this much weight in teh nose before
 

That the second comment about the engine,, What's wrong with it mounted that way? A motor doesn't care which way the head is pointed,,, These designs have worked just fine for many many decades,, every trainer plane you can buy has the motor pointed up like that.

Sorry guys,,
I'm calling BS on that one, Please explain how the motor mounted Vertically causes "tank problems" ??
with proper muffler pressure there should be no problems at all.

RE: never put this much weight in teh nose before
 

If you are talking about mounting the tank in the cowl, it would have to go under a vertical engine. With the engine on it side, the tank can go beside the engine, keeping the tank levelwith the carb. .

RE: never put this much weight in teh nose before
 

I suggest attaching the weights to the engine's support only, in a way that the cooling air is forced to go around the cylinder before reaching the hot exhaust outlets.
I noticed that the cowl has wood baffles for that purpose, but they can be reduced in size or removed if the weights occupy their place.
Consider blocking the lower portion of the big round intake, since the hot air exhaust area should be bigger than cool air the intake.
The air expands when heated inside the cowl, and if there is no enough area to exhaust, you will have hot air re-circulating over the cylinder.

As advised above, make the cowl as light as possible.

Don't go crazy about locating the weights at the extreme nose; one inch of shorter lever (distance) to the CG does not mean one additional Ton of weight.
Remember that balance is between two antagonist torque's (weight X distance) around the CG, one trying to pitch the nose up (weight X distance) related to the tail, the other trying to pitch the nose down (weight X distance) related to the nose.

Don't forget the lateral re-balance after you finish with pitch balance.

Best regards!

RE: never put this much weight in teh nose before
 

Ok one question, I recall seeing a royal / marutaka bear cat much like yours with chrome monokote on ebay form sale, no flaps and fixed gear is thi the one?

Also, with these great scale kits they do require a bit of lead weight up front. My .60 sized royal corsair took about 2 pounds maybe more of lead in the nose to balance! and weighs 14 pounds!!!! see pics


also check out our great threads on royal / marutaka kits:

kit listing http://www.rcuniverse.com/forum/fb.asp?m=9401552

royal kits http://www.rcuniverse.com/forum/fb.asp?m=6667128

balance point and control throws for bear cat http://www.rcuniverse.com/forum/fb.asp?m=9589702

royal fw-190 http://www.rcuniverse.com/forum/fb.asp?m=5620546

royal plans http://www.rcuniverse.com/forum/fb.asp?m=8633292


and many more

RE: never put this much weight in teh nose before
 

I have NEVER added extra weight to balance a model.
I'd go with several of the posts here - move stuff forward. Get whatever you can ahead of the CG. I had to fix a friend's Ultimate once, and moved all servos ahead of the bottom wing into the nose on a sliding removable tray with the ni-cads to remove 3 (yes 3!) pounds of lead ballast. The plane had been built tail-heavy. I usually tape all components in (or on) the plane where I want them, and if there's an issue, start moving things.

Sometimes, accessibility can take an extra few minutes, but it beats trying to fly a "lovesick Pelican" any day...:D