This post needs to stay on tract and the name calling needs to stop or it will be closed down and could lead to action's against the guilty parties. Thanks Dave, RCU forum moderator.

I did post an apology. It is understandable why he would feel bad. Thats a lot of monet to shove in the ground. I guess we could have been a little more sympathetic toward him. I am sorry for what I have said. Maybe he could have told us what could be done differently to avoid it happening. A ll I'm saying is he could have gone about expressing his feelings a little nicer and he probably would have gotton further in the long run. Both with ACE and with help from us.
I feel that this is a new page and that everything negitive that was said on previous pages should be forgiven and forgotton.

Just my 2 cents.


respectfully, Brian

Well.........

As I was picking my left landing gear off the tarmark after my second flight yesterday, I was amazed that the entire gear mount block (which is quite sturdy) was only attached to the wing ribs (rather poorly), and not glued to the leading edge or the main spar. Is this for real? And i just popped loose from the ribs, didn't even crack any.

On another note, the YS 110 is getting faster. She loads up quite a bit in the turns, but on a good steep, high speed pass, she's fast! Partway through the flight the engine lost power and then came the landing. The endcap to the muffler was rolling around in the cowling - hope that explains the loss of power.

I have a week to get her ready again, what the easiest repair of the gear mount prob, new blocks between leading edge and main spar?

DT

DT,

I'd suggest you look into how Vampire installed new retract mounts. He seems to have cured his retract mount problems.

Slightly OT but RB related : What brand/size prop are you runnning and what engine, YS110 or something larger ??

I'm installing an ASP 1.08 Redhead, this is the old high compression ABC engine designed for FAI fuel. It easily swings a 15-8 @ close to 10K RPM running 10 % Ducted Fan Fuel, IIRC the mfg recommends a 16-6 2 blader. I'm thinking of starting with an APC but I'm not certain where to start for sizing. The APC site lists some LARGE props, 15-13.5 sort of things. I also see thay have a 13.4x13.5 listed for 1.20 4-cycle engines. My 1.08 will pull most props suited for the 1.20 4-cycle. I do have a Graupner 14x7 3 blader that I've never mounted on the engine so I have no idea what the RPM or thrust is like on this engine. I'm wondering if I should try one of the big 15" APC props and trim it down in length to achieve a proper load based on RPM. The downside of the APC props is the cost, $24 bucks for test purposes is kind of pricey. I'm also wondering what effect the HUGE cowling and the shrouding of the prop will have on prop selection. I know 3 bladed props are less efficient but they also load the engine more. I also think the so called rule of thumb (go down 1" in pitch and diameter or something like that) for prop sizing a 3 blader is suspect.

Since I know I can pull typical 1.20 4 cycle sizes, what prop size in a 3 blader would be a good starting point ??

Rich

all of you folks have a nice day.sorry if i was a little up set. have a nice christmas and new year

Way to go Drag Racing cars....appology accepted, No hard feelings, and keep talking to Anthony at Ace...Squeaky wheels get the grease....just don't be a jerk over the phone!


DT, I think it's about one page back, but there are some pictures of what I did to my gear mounts. ou could probably even do it withuot cutting anything away. ......

T-pacini, thise are the 85 degree 550's (I think they're 551's since they're 85 degree) . Without acreful measuring, and just looking.... It seems like in order to get the wheels in flush, the top of the mounting plate would have to be where the bottom is with it stock (looking at it with retract well facing up) ...if you follow me. Oriiginally I had my struts set so the offset was facing out to try and get the wheels to tuck in better....but alas that's not scale.

Rich,

I'm running a YS 110. I've tried a Master Airscrew 14 x 9, didn't turn too fast. Had a Graupner 15 x 7 3 -blader on yesterday, but it only turned about 8900. I know the Graupner props are much wider than others, so I'm not sure where to go now. Maybe the same prop by a different manufacturer.

HighSierra, what prop do run on your 140?

DT,

Thanks for the feedback. I have a Graupner 14x7 3 blade so I guess I'll open up the spinner openings for it and give it a try and then go from there.

Rich

I've been running a master airscrew 16/8 on my 140. (It was spinning 9200 on the ground with a fairly rich setting)... Since the Bear has been in the Hangar, and I only had the 140 on for 2 flights, im still not sure if it's too much prop or not. I think graupner makes a 15/8 which I might try.

How about installing the new YS 160DZ...[>:]

cha-ching

I hope we don't have any hard feelings!! Happy new year and merry Christmas!!

P.S.

I hope we can still calmly talk to on another peacefully and put what's on page 24 behind us and just start "a new page".
also, it is understandable why you were upset about crashing an expensive airplane. It has or will happen to all of us. (Hopefully not alot)!!
Thanks,

Brian

Why you gotta be so tight, HighSierra.

I think it can be yours for under 700 clams!

DT

Robart says they used the 551RS retracts, 661L & 661R struts, and the 188VRX air system in their TT Rare Bear.

How about my theory on the stab failures?????

Hello Everybody,

Have been reading this thread for a while. Quite interesting !

Just jumped back into assembling my Rare Bear.

Will be doing the suggested reinforcement modifications to the retract mounts and had planned on recovering the lower sections of the wings, but a small problem came up. Does anybody know the brand (UltraCote, MonoCote etc.) and the color of the covering material. The color appears to be slightly off-white.

I have a couple of rolls of white covering in my stock, but the color is not correct.

Thanks

T-pacini,

I believe your theory about the downthrust contributing to the horizontal stab failures has merit. It's pretty obvious why this could be a possible cause of the failure in highspeed flight. The excessive downthrust does two primary things to the flight dynamics. It's imparting a nose down torque around the lateral axis which means the elevator is having to create a larger opposing downforce to counteract this force. The excess downthrust also requires the wing to create more lift to counteract the same force the elevator must counteract. This increased lift requirement adds and even greater downforce. This is due to the aerodynamic center of pressure exerting an upward force behind the center of rotation of the aircraft. Of course there are a host of other forces involved that we haven't considered. This is also why the plane will be slower in level flight, the excess lift forces required creates higher induced drag and the plane is slower as a result.

I've modified my firewall and decreased the downthrust to 2 degrees. I'll shim the engine mount to establish the exact position for my RB and engine combination as I fly it. It will be interesting to see if the high downthurst was used to counteract an incorrect wing incidence setting, or was it to allow less down elevator when flying the RB in inverted flight ??

Rich

P.S. I checked my horizontal stabs and the root ribs which mate/glue to the fuselage are lite ply. I can't easily tell what the inner ribs are made of.

Hey guys.. Out of curiosity: What is the distance from the front of the cowl to the back of the spinner plate supposed to be? I am asking cause it seems like you all are having to add nose wieght if I read correctly.. If that's the case then why not slide the engine forward? This will do 2 things..
1. Balance your plane with an overall lighter wieght..
2. Boost your propeller efficiency..

I fly the Extreme Flight Yak-54 which is a radial design and the full scale prop is way forward of the cowl for prop efficiency.. We put out motors 3/4-1" out on the models for this reason.. Just my $.02.. Let me know your opinions.. Thanx

Joe:

The flight surface covering is White Ultra-coat.

To Rich and others,
A good observation on the down thrust and it's potential affect on Stab failure, I just wish to add that I have MANY flights on my RB now w/ the OS 1/60 FX , w/ stock down and Rt. thrust, with a stab that has a BALSA root rib and I have had NO issues in this area to date.

I believe that one other aspect that is possibly being overlooked is Elevator Flutter resulting in the stab departure.

To insure fluter does not arrive at your door step, make sure the elevator pushrod system has NO PLAY in it and that when installing the Elevator to the Stab., NO GAP should be present in the hinge line of these 2 components. If when your done hinging, you have a gap, cut a small strip of the white Ultracoat or clear PVC packing tape and seal this gap on the bottom of the surfaces. GOOD insurance but NO substitute for any play in the pushrod system.

Best of luck to all and a Happy Holiday Season.

Vampire,

I don't like to use the "F Word" in public, hence no mention of Flutter in my post. - lol

I agree, control surface flutter might well be responsible for the tail seperations.

Rich

So summing it up.... I'd think these are the probably reasons for tail departure... Too much down thrust, flutter, a balsa root rib, and assembly error by the end user. I think way back at the begining, when they first came out, someone had the stab depart in flight, and they said ace replaced the whole plane due to lack of glue from the factory... If I remember correctly, I think mine had a ply root rib on the stab, and I bought mine in early september.

For those who have changed the down thrust... do you remember what it was stock?

....The good book says 6" from the firewall to the back of the spinner...you could probabally stretch that a little.... no more than 1/4" i would say, before things start to look out of shape..that woud give you a spinner rear/cowl gap of about 1/2"..[:-]

I moved everything as far forward as possible, with a Heli " C " spec .91FX and recomended type retracts got the Bear Rare Balanced correctly, ready to fly with an AUW of under 10 Lbs..

I put a lighter Sprung, Sullivan Tailwheel in too..it all helps.

DT,

Did the prop save your value cover again? Hope everything is fixable. Sounds like it's time to really get into her and beef it up (as Vampire has been suggesting for the last 3 or 4 months now). Interested to hear if new prop selection worked better for you than the MAS 14X9-3. Hope to come your way again soon. Don't break her before you get John.P's signiture on her!!!

Reply to Vamp's Post #740

Thanks Kerry !


Joe

Have been trying to search this LONG thred with no luck. Getting ready to order parts for my xmas RB. I am going with mech retracts. I have a set that are 5/32. Is that OK??????

Also, I read somwhere that I should get larger and lighter wheels. What size? Any specific product/brand would be appreciated. Ordering everthing from tower.

JWortner,

I'd stay away from retracts that have 5/32" wire legs, especially if any portion of the retract's trunnion is made of molded plastic. This type of retract is meant for the old E.Z. and Lion Model's (E.Z. clones) ARF kits. These planes typically weighed 7-8 pounds and the mechanicals were barely adequete. If the mechanicals you have are Supra mechanicals ( they should be all metal) then you could probably use them in combination with 3/8" Robostruts. A low cost alternative is a set of Spring Air #116 with 3/16" wire legs. You could probably get a set for about $100.

The only reason for lighter wheels is to make it easier on the retracts. If your flying from pavement you can use a smaller scale diameter wheel. If you fly from grass, then taller 3-1/2" wheels are better. I'm using Sullivan 3-1/2" Ultralight wheels with the aluminum hubs.

HTH

Rich