RE: ThunderTiger Rare Bear
 

Well, I flew yesterday with the YS 110... Signifigantly better than my 91AC....but since there's no weight change between the two, I called Central Hobbies yesterday afternoon and got a fz140. No place to whine about power now :D

Should have it all set for tomorrow!!

RE: ThunderTiger Rare Bear
 

P-51B,

You are right, there are pros and cons to each. I guess I should have clarified something. When I started flying again (after 20 years off, back in my "day" when I was 15 and flew .15 size glow, there was maybe one guy who would take your plane up 400' and then give you the controls... needless to say I wasn't in love with it as I couldn't even SEE it!) I decided to look at glow and electric. I had a few months off and was planning on flying every day, maybe 8 flights a day. When I looked at the cost of glow fuel (64 oz. per day, 5 days a week, 2 1/2 gals per week - $45 a week x 52 weeks (hypothetical only, my Wife might object if I quit and flew full-time) came to $2,350 a year. Using that figure, I saw that electric isn't more expensive, if you fly a lot it can be significantly cheaper. The field I fly at even has 110 outlets on both sides of the pit area.

Anyway, take that, along with not wanting to have glow fuel around the house (2 year-old) and having 2 new cars and not wanting them to smell like fuel and you have enough to push me towards electric only (I do not own a container of glow fuel, a starter nor even a glow starter). I also have a problem with the greasy feel of everything after flying with glow fuel, I cleary remember that as a kid. It gets on the plane, on your clothes, hands and everything else that you touch. I even get irritated when someone at the field fires their engine up in front of my electric and I end up breaking out the windex wipes!

Seriously, they are both viable options and both are extremely fun no matter which way you go. In the future, we will all be flying electric anyway, there is simply a finite supply of fossil fuel (yea, we might go alcohol but the world will likely be completely electric some day). Competitions are being routinely placed and some won by electric today, it seems like it's "in" now...

My 2 cents anyway... Also 1/3 the price of flying one time! ;-p

Jack

RE: ThunderTiger Rare Bear
 

Have you considered using the graupner 15x8 3 blade on your axified bear? Greg Covey used that setup in the H-9 corsair.

RE: ThunderTiger Rare Bear
 

Yea, my original idea was to use a 3-blade (I purchased a Master Airscrew 14x9 3-blade) with the included spinner but the prop is simply too thick. The Axi uses an 8mm prop shaft adapter which is quite substantial but even with it's large size and length a spinner backplate, standard prop and washer leave only 1 turn for the nut. I was not comfortable with having only 1 turn so I had to scrap the idea and go back to the APC electric 16x9. I chose that using MotoCalc as the most prop for the Amp draw I can support.

I may have to work out something though because I am still an inch too far back in regards to CG. I don't yet have a 2-blade, 4" spinner (tomorrow) so I don't know if it will be enough to tip the scales. The 3-bladed one htye supply is HEAVY, I know using it I would be OK, just have to figure out a way to mount a standard (thick) prop...

Jack

RE: ThunderTiger Rare Bear
 

HighSierra, can't wait to hear your report with the 140, that's almost cheating!


Here's my thought for exhaust: basically straight pipes split to exit each side, what do you guys think?


[img][/img]

RE: ThunderTiger Rare Bear
 

Can't seem to upload a photo right now, says error saving file.

Will try again later.

RE: ThunderTiger Rare Bear
 

lord lucan.....where are you in the uk?

RE: ThunderTiger Rare Bear
 

..D.T. ? ....;) ....Middle bit..ish..;)

...Looking over the bear a bit more [:-].....quality excelent.. instructions ..so, so.....lots of room to manoever on a few points...tanks got to go up for sure...servos to the front...?

RE: ThunderTiger Rare Bear
 

Hi Jack:

Thank you for the info. I have had no idea of the investment to go E on such a large aircraft and get respectable performance. I have little to no background in Electrics but working with my brother who just started kitting electic aircraft (www.classwings.com ) I have learned just enough to be dangerous !

I was born into this sport on glow burners in 1961.

Being a model designer and mfg. for nearly 25 years, I like folks who think outside the box. ;)

Looking forward to your flight review with this set-up.

RE: ThunderTiger Rare Bear
 

Okay it seems RCU doesn't support my browser for uploading photos anymore.

Thinking about trying this for exhaust.

[img][/img]

RE: ThunderTiger Rare Bear
 

lord luc.....

yes D..T..

just finishing the tailplane at the moment, rudder doesn't line up, everything else is pretty good, used standard Eurokit retracts from Inwoods in the wings with foam wheels, i'am installing the servos in the postion shown in the cradle and not moving them forward, couple of things missing from the kit but on the hole not bad..seen worse!
did strenghen the retract area with some spare bits of kevlar, should hold up the Titanic now, didn't add hardly any weight if it's done right.

still not sure on engine.....ST2300 looks a firm favourite, will see how the other guy on here does with his, is that or a laser 150, will see.

what you putting in yours...Luc

post some picky's when it's finished....hopefully next week

cheers

dave

RE: ThunderTiger Rare Bear
 

CG!!!

Does anyone know the F8 or Rare Bear flying characteristics well enough to tell me what to expect if the CG isn't per recommendation? I really hate adding nose weight to an electric (any weight to tell the truth) and right now the CG is about 1 1/4" behind the recommended point (forward of the wing tube but aft of the wheel well). I fly other smaller planes with the CG 1/2" - 3/4" with no noticable difference but I haven't fown a warbird before...

Comments?

Thanks in advance...

Jack

RE: ThunderTiger Rare Bear
 

Mine has been about 1/2" aft of the book as I just couldn't bring myself to add anymore lead... BUT..... Since mine is a glow, and the tank of fuel is forward of the CG my info may not totaly pertain.... But with it the way it is, it flies slightly nose heavy if anything. I think I'd be a little nervous about flying it that tail heavy right off the bat.... Be aware that it is somewhat of an elevator sensitve plane so starting too tail heavy could spell disaster....

RE: ThunderTiger Rare Bear
 

Thanks for the info...

But... forgive my ignorance, I only fly electric... Isthe CG measured dry or loaded with fuel? I guess measured dry means you are likely taking off with the CG in the correct place (maybe even forward?). If measured wet, you are landing with the CG well aft of the recommended location.

Thanks again,

Jack

RE: ThunderTiger Rare Bear
 

aps f4u: Which muffler did you install in your ST 2300? The original ST ? Does the ST 2300 fits well within the cowl?

RE: ThunderTiger Rare Bear
 

CG is measured dry jfetter

RE: ThunderTiger Rare Bear
 

Yea, I was hoping not! I sat down and played around with weights and realized I'll have to add 15+ oz to the nose of this thing to get it close (not exact)! Am I nuts or is this a terrible design? Don't get me wrong, I love the plane but having to add so much weight is painful. Can I fly it with the CG 1 1/4" back, is this completely crazy? I have a 14.5 oz motor mounted 5" forward of the firewall (Axi 4130/16), this would SEEM to be more weight that the standard power plant placed even farther forward?

Not sure what to do for tomorrow AM's maiden flight...

Jack

RE: ThunderTiger Rare Bear
 

Jack:

Your condition is very obvious in that with your motor only being 14.5 oz and adding an est. 15 oz. (29.5 oz total ) to make the recommended balance is RIGHT ON as my RB balances perfectly with NO ballast what so ever with a 33 oz. Glow engine + the muff. !

You can go as far aft as 30% of the MAC (mean aerodynamic chord ) and still have a flyable craft. I have performed a very quick calculation and find the MAC at about 12.25 to which 30 % = 3.675 in. or say 3-5/8 in. to the CG ON this MAC chord line ( this is NOT measured at the root of the wing ). This is based on memory of the dimensions I took the other evening to determine wing area and loading. I cannot locate this chord line until I measure the actual model again. I can perform an exact calculation this afternoon and will advise.

Be on notice that the fruther AFT you place the C/G, the more sensative the Elevator will become. Be sure to set your dual rates to deal with this.

One other suggestion is to remove the supplied tail wheel assy. and just put a wire in for the maiden as this will allow the balance to move forward requiring less nose weight. In addition, Higgley products makes a BRASS ACORN nut and PRATHER products makes a steel weight that looks like a washer, both can be installed on the motor shaft to help with the balance as this allows weight to be added at the forward most point of the aircraft.

The only drawback, and it is minor, is that these weights will add a bit of flywheel affect to the motor which will cause the motor to speed up and slow down bit slower in ref. to throttrle command inputs.

Just FOOD for thought.;)

I will get back to you on the calculated C/G range later today.

BR

RE: ThunderTiger Rare Bear
 

Not to mention that the full scale Bearcat had a HUGE freakin pratt & Whitney on the front end which weighed a crapload. To make this ship look anything close to scale the nose had to be kept short. I hate when models have the nose extended to try and compensate for balance such as that Hanger 9 T-6, the Cyrano deBergerac of ARFs.

RE: ThunderTiger Rare Bear
 

Vampire,

I appreciate any advice you can offer, adding weight to an electric (even though it wil still perform acceptably) is a last resort. If the plane if flyable with only a small noticable effect, I'm all for it but obviously I don't want a squirrely craft either. The picture was a little confusing because they show the CG right in front of the canopy, but reading more showed it is the panel line in front of the canopy and the picture is wrong. I ended up measuring to be sure.

I love the idea of changing the tailwheel, that might be a great suggestion as a few ounces that far back will have a huge effect in the front. I'll watch for your post and let you know the outcome. I was to fly today but I seem to have come down with the andromeda strain, I feel like I was beat with a stick...

Thanks again,

Jack

RE: ThunderTiger Rare Bear
 

Dave ...This Bears been buggin me somewhat ..[:-]..the wing is really quite err...not huge ;)....lets be generous and say 5.4 Sq ft @ 62" odd, so If you could get the AUW down to 10 Lb you still be up near 30 oz/Sq ft (29.6) ...thats drifting towards the edge of the comfort zone for me...

The ST weighs 31 oz..WITHOUT a muff.. AN O.S .91FX "C" spec helli standard weighs 21oz ..again no muff ..3.0 BHP...

I know ballance is going to be a big issiue, but moveing all radio as far forward as poss is going to help, new control transports, Golden rods ?.. Supra 60 sie mechanical retracts..(used these before,excelent), lighter tailwheel, 6v 2300 MaHr batt pack up front, slimline Pitts muff for the .91FX @ 84g, new lighter wheels, the obligatory "Voltwatch".

Be nice to get this thing under 10lb's ...dont know if thats possible...;)..here,s another .91FX "C" spec in the CAP 232...;)

RE: ThunderTiger Rare Bear
 

The balance thing has me a bit worried as well. Not very easy to move the radio gear forward. I've moved my retract valve servo up to where to book shows the mechanicals, and I never know that pnuematics where so heavy, but at least they're near the cg.


DT

RE: ThunderTiger Rare Bear
 

Hey Desert Toad,
Is that steel brake line that you brazed up for your exhaust? If so, how did you adapt it to fit up to the engine? I like to make stuff like that up too, and was just wondering how you did yours.
Thanks,
Alan

RE: ThunderTiger Rare Bear
 

I used a Bisson pitts for the ST 2300, and yes, the 2300 fits beautifully inside the cowl, although I did mods to my pitts so I wouldn't have to exit the exhaust stacks out of the bottom of the cowl.:D

A

RE: ThunderTiger Rare Bear
 

Just finished up putting the stickers on and few other things, now it is finaly ready for its first flight tomorrow and I hope I at least break 100 mph with this Bear. Wish me luck....Oh ya, weighed it just after I finished, and it came in at a toatal fo 10.5 pounds! pretty light I thought anyway, especialy when the box calls at a total weight of 11 pounds.