Detlef Kunkel

Mitch, I am also looking forward to your build.
To be honest I never measured the thrust line of the engine. When I built my Firewall / engine Mount, I only centered the engine to the cowl ( concerning the down thrust).
No side thrust.
The Cat flies very well on that.

Also; nice work on your gear.

Since last month I am also working on a scale gear. Not much to show until now, more designing and construction work.
Together with a friend we are going to produce scale gear sets for 3 BC´s. (one for him, one for my old BC, and one for my son´s BC.

The main concern is not to be 100% scale, but to make it stand upright like it should, and to be 100% functional and reliable. My pal is rather going for electric Motor drive, I am not doing that. I will build reliable big cylinders for gear and doors again.

Another friend had constructed a semi scale gear and made one pattern with a 3D Printer.

At the moment I am modifiying it to sort out the last issues, und we are changing the mounting structure completely.

mitchilito

My Feedback: (7)

Detlef, I'm looking forward to seeing your landing gear solution. I'm pretty confident mine will hold up but the cylinders are a little small. There's not really room for bigger ones so I plan to run high pressure - maybe 130+ - and if that doesn't work I may go electric.

I just checked the angle at the cowl opening again and there's about 4 degrees downthrust. That's about 2 degrees more than I would expect. So, if it is too much I would expect the airplane to need up elevator trim in full power level flight then climbing on throttle reduction. Is this the case Detlef? Of course this assumes the CG is in the right place.

Who knows, maybe it's just right and if so, I'll leave it alone! That's what so great about these forums. We don't have to make the same mistakes over and over again!

Detlef Kunkel

Mitch,
it depends on what you take as ZERO Reference line..
The wing is not positioned at zero angle in flight. It might have between 0,5 and 1 gegree incidence to produce lift.
I guess the engine has not 4° downthrust in flight.
But look at the sideview of the original Hellcat or Bearcat, their engines really Point downwards.
Whatever the theory is- the Cat flies well and neutral enough when inverted. This shows that the setup and CG is OK.

mitchilito

My Feedback: (7)

Detlef, that's good information. Thanks. I will use the geometry 3W built into the airframe. I'm busy working up a new (BIG) more scale cowling. What a chore. I sure wish 3W actually produced a Rare Bear kit - instead of a bone stock F8F with clipped wings. But I'll quit complaining now because I knew full well what I was getting into :-)

mitchilito

My Feedback: (7)

Here's a couple pics of my cowl progress. I thought about making a mold out of the plug but decided to just glass it instead for a "one off." White is ready to glass, red is glassed (my West Systems hardener has oxidized to a DARK red).

vatechguy3

My Feedback: (11)

Any updates or progress??

tony

Billy J

My Feedback: (4)

Awesomeness

schoenki

Hi guys,

i want to show my on created electric scale tail gear. It is for the 3w cat and scale as possible. It weight 345gramms and will be drived from a firgelli actor.

kind regards,
chris

rbgetz

Nice tail wheel. Sierra made one similar to yours, but where did you get that wheel.

schoenki

I do on my own.
It's a 3D printed part.- the rim material called alumide and the rubber tyre is from a bought wheel
chris

mitchilito

My Feedback: (7)

I just looked at the date of my last post. Holy Cow it's been a long time! Time sure flies nowadays. . . .

Anyway, progress has been slow to say the least but lately I've actually been putting in some hours. My problem at this stage of my life is I don't want to do anything that isn't fun - and working on this project has NOT been fun. It's getting better now though since I'm starting to see light at the end of the tunnel. Or is that the headlight of a train???? He he he he. . . .

SO: Here is my answer to the cooling air exit dilemma with that big ole Moki 300. The rare bear has bigger side exits so I increased my exits as well and then as you"ll see, I added a large exit on the bottom of the fuselage. I didn't want to cut the bottom of my cowl all to pieces although I probably will still remove a little bit just ahead of the fuselage cutout. The motor will be tightly baffled as well.

mitchilito

My Feedback: (7)

Did I mention that my West Systems epoxy oxidized red?! It's easy to see where I've been working. . . .

I was shocked and disappointed to see that the horizontal stabilizer was not plumb with the wing! So, I had the choice of cutting the wing tube free or the two H-stab tubes to align them so I chose the H-stab. You'll see where I freed then reglued them. I then made a rudder servo mount to attach to them. I will not comment further on the factory misalignment. . . . .

mitchilito

My Feedback: (7)

Shoenki, your tailwheel retract is beautiful!

Speaking of tail retracts. . . . .I liked Rob's Sierra tailwheel assembly enough to order one. I wanted to eliminate the steering cables so you'll see my answer to that - I built the servo right into the mechanism. I don't really have to worry about the tail weight and it works great.

mitchilito

My Feedback: (7)

This thread is such a valuable asset. I would've had to spend my valuable money and time trying to zero in on the right propeller for this exact airframe and instead I knew EXACTLY what to get. Thanks Detlef and Rob!!

Here's my gorgeous SL 30 inch 4-blade prop with the "new" blades.

mitchilito

My Feedback: (7)

Looks pretty simple in the pics but it was not easy to hinge the tail surfaces. My hat is off to the other builders of this particular airframe! I have added all control horns and routed the wire cables to the rudder since these pics were taken.

mitchilito

My Feedback: (7)

I decided a while ago that I really wanted the 2-into-one exhaust that Voglesange sells. Only one proplem: Gotz only offers it for the 250. He told me a version for the 300 would NOT be forthcoming. After discussion he thought that the 250 version MIGHT (no guarantee) fit up on the 300. Well, it didn't and I was really disappointed. Like I said, I was determined to have 2-into-one SO:

I manufactured a tubing bender in order to tweak the additional angles that were needed to fit up to the 300. It wound up being a major project but I now have my 2-into-one :-)

BobH

My Feedback: (2)

Pretty handy making the to be bender. Good looking project.

rbgetz

Mitchilito... I switched from the SL standard Hamilton blades to the new wider scale 30" blades. I notice better performance at same RPM. Getting the pitch just right took a a few tweaks. An they look really nice. Most people that see the prop for the first time think it's just a display static prop. My bearcat weight at T/O is around 55 lbs, but you wouldn't think so with the pull from the 300 and the 30" blades. This is one aircraft you never get tired of flying.

mitchilito

My Feedback: (7)

Rob, those are the same blades I have. I pitched my as far as they would go: about 21+ inches. They quit wanting to turn in the sockets anymore than that. I can't wait to fire this baby up! Have you been flying yours regularly? Howz it holding up? Does the 300 run cool enough with your air exits?

I've made quite a bit of progress lately but I'll have to post it later - from my iPhone where all the pictures are!

mitchilito

My Feedback: (7)

After much thought I made carbon fiber plates for the elevator servos to mount on with machined aluminum brackets. I installed carry through spars for the plates to mount to. Incredibly strong -and light.

mitchilito

My Feedback: (7)

I made carbon/plywood sandwich stock for the tail wheel bulkhead and somehow managed to get it installed way back there in the right place - more or less! (Aeropoxy fillets not applied yet)

mitchilito

My Feedback: (7)

For the fuselage bulkheads I did a vacuum composite layup of 4mm high density foam with 4 layers of carbon cloth. I made three 18 inch sheets. Just for fun I priced similar stock at my composite supply- APC. As I recall it was the better part of $100 sheet!! The stuff I made is very strong and once the bulkheads were cut out they weighed practically nothing.

Don't ask me why RCU wanted to turn my pics sideways! Sometimes they do and sometimes they don't. . .. ..

mitchilito

My Feedback: (7)

Rob, do you know what your final pitch was? Did you use the wood gauge that comes with it?

rbgetz

Hey mitchilito... The bearcat is holding up great. I'll check the pitch and get back with you. II was planning to flying it at an event coming up next week but have had some radio trouble. So I want to swap out the RX before I fly it again. just a precaution. yours is looking really nice!

Rob

mitchilito

My Feedback: (7)

I've been dreading it but it's time to tackle the rare bear canopy. I knew when I bought the kit the stock canopy is wrong. It stands too proud of the fuselage. Trouble is, to chop it down requires major work on the canopy frame. Picture 1 shows stock. In picture 2 I dropped the canopy down in the frame approximately where it needs to be - just for reference.