T-bird 2 engine options

[rob biddle]

 Hi all, just started on an RSM "Thunderbird 2" kit the other day. (will post some pics soon when  the "better half"  brings home the camera from work)
 Just wondering what I should use for an engine.
The choices currently consist of.....
 1. Merco .35.
 2. OS .35 MAX "S"
 3. Brodak .40
 4. OS LA .46
 As calm days are fairly rare here now I'm leaning towards more cubes, probably LA .46, I've seen a couple with ST.46's and they did it real easy.
 I think the extra cubes will allow me to carry a little more construction and finish weight (still aiming for sub .45 oz) to hopefully make it last a bit longer.
 I really want to save the B.40 for the Kismet which I will be building next, it was designed for a Merco .35 and has a fairly short nose.
 I was going to run the LA .46 in it but I don't think it will carry enough fuel with out extending the nose and requiring a heap of tail weight to compensate.
 Would be keen to hear peoples thoughts on this before I am committed.
Thanks, Rob.

[Jim Pollock]

Rob,

I have the RSM kit of the T-Bird and have two OS LA .46's - One of which is slated for installation in that airplane.  Hope this helps some?    A good combination from what I understand.....

Jim Pollock


Audacter et strenue, or in plane english "Boldly and Strongly"

[Bill Little]

Hi Rob,

Propping the LA 46 in the T-Bird 2 will be the only consideration I would have in that set up.

The 46 likes 11 1/2 inch or so props so a 3 blade might be the way to go without having to do a lot of LG modifications.

Otherwise, I think you will really like the LA 46 in the T-bird! 

Bill <><

[George Waters]

I have twoo rsm tbird II models. Both have rojett 40 re engines in them. Plenty of power and both balance on the edge of the spar. Iwould say use the os 46 on it prop clearance with 2.25 in. wheels should be ok , one of mine runs an 11x5 pro zinger and the other is an 11.25 gator prop. You will like this plane a lot. Take your time with the wing tips as they can twist up if your not careful. Enjoy.  George

[Bill Little]

I have twoo rsm tbird II models. Both have rojett 40 re engines in them. Plenty of power and both balance on the edge of the spar. Iwould say use the os 46 on it prop clearance with 2.25 in. wheels should be ok , one of mine runs an 11x5 pro zinger and the other is an 11.25 gator prop. You will like this plane a lot. Take your time with the wing tips as they can twist up if your not careful. Enjoy.  George

Good to hear about the prop clearance, George.  My plans built T-Bird 2 from 15 years ago would barely clear a 10 1/2 inch prop on pavement.  I know the LA 46 needs a 2 blade in the 11 1/2 inch range.

Bill <><

[rob biddle]

 Thanks  gents,  pretty much decided last night that the .46 would be the way to go, glad to see that is the general consensis. 
 
 I put a couple of props over the plan and you're right Bill, there isn't really much prop clearance! Could pose a problem as we only fly over grass here.
 Might bend up some wire gear for more clearance.
 
 Currently toying with the idea of trimming back a 12x5 zinger (wood) to about 11 1/2". It would give nice wide blades, had pretty good results with APC 11x6 but I'm thinking that  bit more diameter and less pitch would be better.
  I've been running it in a fast 4 stroke (previous model was only nobler size) and I'm pretty impressed so far. 
 
I'm also looking at changing the bellcrank mounting to use a couple of ply strips top and bottom that span the middle 3 bays, never really trusted bellcranks only supported from underneath!
  Should get some photos posted tonight hopefully, thanks again.
 Rob.

[Leester]

Rob: FYI The Brodak Accentor landing gear is much more sturdy and about 1/2" longer and is wider than the gear provided and will fit the mounting plate. Also the fusalage tail post at 1/4" square doesn't give you much room for elevator control hook up you might want to consider something a hair wider 5/16.

[Bill Little]

Rob: FYI The Brodak Accentor landing gear is much more sturdy and about 1/2" longer and is wider than the gear provided and will fit the mounting plate. Also the fusalage tail post at 1/4" square doesn't give you much room for elevator control hook up you might want to consider something a hair wider 5/16.

Thanks for the heads up on the Accentor gear, Lee!

As to the narrow tail end, I have resorted to using scabs on the outside blended into the fuselage side to give enough room for an adjustable elev. horn with out having to change the tail width.

Bill <><

[john e. holliday]

Nothing wrong with using larger wheels on an airplane, which is what I do quite a bit flying out of grass most of the time.    DOC Holliday

[Leester]

OK Bill: Your going to have to explain this SCAB thing or a pic would be nice.  Thanks

[Bill Little]

OK Bill: Your going to have to explain this SCAB thing or a pic would be nice.  Thanks

Hi Lee,

I build the fuse as per the plans first.  Then I cut out the area that the horn (and bolt, etc., on the adjustable set up) needs from the fuse sides themselves.  Now you have a smicircle slot big enough in the sides to not allow any interference.  When you have that done, cut out "scabs" from 1/8th, or so, balsa big enough to overlap the open areas.  I take them all the way up to the stab in front and fillets in back.  These get sanded on the edges and smoothed off on the sides to blend back into the fuse sides.  I then leave a small vertical slot to get to the socket head bolt on the adj. horn. 

When finished and painted, it blends right in, and gives a touch more "area" to the fuse where the stab locates without adding any weight so to speak. 

Mke sense?

Bill <><

[Leester]

Thanks Bill, I'm pretty sure I get the picture.