I posted on the giant scale forum but havnt received any input. Im building the Ziroli 86" Bearcat and trying to decide what to use for power. I am aware of Quiros Bearcat with a BME-102 twin but that just seems excessive. I want to fly at scale speeds, mind you the full scale was/is a rocket in vertical. No prop plane could beat its rate of climb, or short take off distance. I want the most power and compact size for the least amount of money......DONT WE ALL????

Im also considering a DA-85 or equivelent. I plan on building 2 wings-full span and clipped. Will use Robinaire or Sierra articulating retracts. I plan on modeling Darrell Greenameyers 1967 "Smirnoff" racer. The pic isnt an accurate example-the real a/c colors were a darker metallic blue trimmed in gold.

Your input and influence is greatly appreciated......

Kev

what weight do you expect from the Bearcat? I will be building a JDM Bearcat at 82" ws and I am putting under the hood a magnum 400 5 cylinder. Now the plans say a 1.8 glow will fly it..........All depends on the flight performance your looking for.

Forgot to mention its gotta be gas. Done with glow!!

Kev, the BME 102 and the DA85 are in the same league - not much difference between them (power wise). The DA85 is a good engine with less weight and less moving parts then a two cylinder.

The DA would be a good choice for your project - keep and eye on Terry's P-40 with the 85, he ordered a 24-14 three blade - lets see how much we can get out of this baby.

Yeah the need for speed...

Happy landings

G-Pete

Kevin, i'd say the DA85 would be a good choice. I've also seen them fly on zenoha GT80's pretty fast too. depending on how much you want to spend you could also look at the RCS 150 Radial if it would fit i think it's diameter is around 8.5 " that would be pretty KICK-*****. It is 10" in diamiter sorry 150 cc way to much for this plane.

Sorry - no offense but the Z80 is a device from the past. This thing weights 7.7 pounds and
"""Delivers a whopping 6 horsepower to drive a 24x10 APC at 7500 rpm"""


May good for a snapper fishing (trolling anchor) but nothing else - Zenoah engines like GM V8's from 1972 - yes they had their place, but today there are better lighter engines out there. Reliable as the Zenoahs ...

Happy landings

G-Pete

but he is gonna need that weight up front.,....especially for a short nosed grumman fighter

Kevin,
Flew mine for years on a Q-52 and it was (Monokoted) up like Howard Perdue’s #14.It was light coming in at 26# but the speed was on the nose. You will probably have to have nose weight like all of us have.I had to add 2 # to the Bearcat so a G-62 or Q-75 that has some weight to it should be great. I am finishing up a new Ziroli Bearcat now and am flying a Ziroli Hellcat that weighs 42#(9# of nose weight) on a G-62 and have been flying it last year on a RCS 150 ( a good friend of mine owns it) and it is a match to the Hellcat.

Good Luck Todd

Thanks for your input Pete-Im leanin toward the DA-85. Less complicated, lighter weight etc only makes sense.......

Kev

Excessive???[sm=confused.gif]

Evan Q.

Hey Evan-thanks for stopping by! Im not trying to be argumentative or insinuate you made the wrong choice. Im sure your choice made sense for you. Im just trying to figure out whats best for me. For me its a matter of engine size, weight and price. If I can be happy spending 600 or 800 rather than 1200 or so, give or take, thats gonna be the logical choice. I want something that will fit in the cowl without much fuss. Im not opposed to spending 1200 but I want to be sure its money WELL spent.

But please, give me your input. I respect your knowledge and experience.

Kev

yes you are

I think I hear Billie calling, Go do your chores dude.
E.

Kev, You can probably find a BME for sale on RCuniverse marketplace for a decent price.

Well I still havnt decided on a powerplant, but I did just get these.........

You'll definitely need nose weight. Mine, with a Q-100 (almost 9 pounds of engine), still needed a dummy radial and about 3/4 pound of lead.....why opt for a lighter engine? As for the BME 102......you should see E.'s bird whiz by. I would go for a heavy engine...old school as I am, I don't see putting these new light weight engines in a short nosed plane like a Bearcat, Tempest, Typhoon, etc.

Jeff

So while I collect all the scale goodies I need for for the Ziroli Bearcat I decided to "un-retire my TF Bearcat. YS-91ac for power, 3blade prop, spring air etc.... done up as Rare Bear US Thrift racer. This one scoots along at 140 mph straight and level. No nasty habits-about 100 flights so far. Built in 2001. Wings clipped to scale-I removed 1 rib each side. All I need is retracts and struts and shell be flying again.

The Ziroli fuse is next to it for comparison


Kev

The YS-91AC produces between 1 and 1.5hp depents on fuel. This gives you about 8000RPM with a 12x10 3-blade - this equals to about to 75mph. You need a 18x18 and 10HP to reach about 140MPH wind Resistance loosely calculated.

There are other factors like super sonic (prop wise), weight and size...

If you would posted a racer with a knife airfoil, 4 pounds and a Rossi engine with 21000 RPM - they make 140 mph.........fast airplane though but not 140 sorry.


Happy landings

G-Pete

FYI

From 45mph to 90mph is the double speed but the wind resistance increases by factor 7!
Here an example:
A good 50cc scooter makes up to 60mph - most of them have 4-5HP. For the record run of 130mph Kreidler needed a 20 inch low two wheeler totally enclosed, the engine (49.8cc) produced 25HP natural aspirated.

Guess this is self explaining

Happy landings
G-Pete

Well, If I remember correctly I used a blended fuels 30% nitromethane. I had an undercambered prop-made by APC. It was a 2 blade with a 3 1/2" spinner. Dont remember what diameter or pitch. The radar gun used was a CHP friends. Maybe it wasnt calibrated Wouldnt surprise me if it wasnt.

I purchased a 3w 70cc engine. I now have pretty much everything I need to get going with the build. I think this engine will do the trick and make me happy.

I'd be curious to see how much nose weight you need to add.

Jeff

Yeah, I thought about that, Im sure Ill need quite a bit. We shall see. But I got the engine with a pitss muffler for very cheap. Cheap enough that perhaps even by the time I actually need to install an engine I may even change my mind.

I googled the 3w70 and found out that the engine and module weigh 5.6 lbs. With the muffler and misc stuff it should be approx 6 lb. so I think I should be ok. Im sure Ill need to add weight, but hopefully not too much.

After thinking about the 3w 70cc engine I intended to use, I decided to buy a new Zenoah g-80 twin. The Zenoah comes with everything I need and is brand new-whereas the 3w was used and missing various items. Plus the Zenoah is more powerful at 6 hp and fits nicely in the cowl. Plus various other folks have used the same engine and its perfect for the Bearcat.

Still waiting for the wheels from Glennis. Its been a month so hopefully they will arrive soon.

Good Choice on the GT-80 I am going to use two of them on my 3W Tigercat, My friend had those on his Tigercat and clocked it AT 140 MPH, That's with 118" wing

Dave

PS,,,,,,,,,,,,,,, You might be waiting a little longer on the rims