I have an unbuilt Brodak Baby Flite Streak and was wondering if my Cox Medallion .09 would be too much power. The Brodak version is slightly larger than the original TF kit and it was designed for .049-.099 engines. If I did go with the .09 would I be able to go with longer lines? I have 35' .012" lines that I fly my Cox Black Widow powered Brodak P-51 on and 60' .018 lines that I fly my Fox .35 powered Brodak Original Flite Streak on. Or should I just go with one of my TD .049's?



Mike

It is nearly always possible to deal with surplus power. It is the reverse that is a serious problem, however, the "suitable" engines for a Baby Streak are going to cluster right around .049 / 051 (size, weight, etc). The Medallion .09 offers a sufficient level of power for the Junior Streak, at 31" span, and 230 square inches of area (and the two are well coordinated for size & weight). I've used an Atwood Shriek, a Cox Medallion 049, and a McCoy 049 diesel on Baby Streaks over the years.

I can imagine using an OK Cub .099, and an OS Pet 099, both of which were nothing special for power, but a K&B GH 09 would be like the Medallion, a large surplus over the need, as would any modern Schneurle 0.10 engine, as well as the Cox TeeDee 09 (and all would require extensive front end modification to handle the larger size cases involved).

I flew a Junior Flite Streak with TD 09, 10% Sig Champion 20% oil half castor, half synthetic, Cox grey 7 x 3.5 prop, 57 ft 12thou lines. On 55 ft lines I was getting 3.8 sec laps, pretty darn fast for an old man to fly stunt with. With the 57's it was just over 4 sec laps and I could fly it OK. I think a Medallion 09 would be fine, maybe better, for a Junior Flite Streak on shorter lines. No way I would put one on a Baby Flite Streak.

Baby flight streak with TD .049 with normal 1/2a lines moves out really well!(FAST)
Convert your motor mount/front of airplane to beam type, Like a big Flight Streak.
This is one of the best flying 1/2a's going!

David

It already has beam mounts.

So presumably when the old kit specified up to .099 they were talking about an anemic .099 engine. Similar to my big Flite Streak which is designed for .19 to .35, I have a Fox .35 on it (because I had one as a kid) but if I were to use a modern engine it would be a .25 probably.

Good to know!

Well then, I'll use one of my TD .049's on it. I have 5 of them and an .051 also. I better start building!



Mike

To "The K."

Have to differ about always being able to handle more than necessary power...

Not on the matter of power, in this case, but fitting it all together... The Baby Streak is a small model! Balance? Tank?

Mike got it right about the engines listed on these ancient kit designs. Not much power from the available 1/2A engines until the Space Hopper, and I'd like to see how anyone could mount that birdcage onto a Baby Streak...

Modern .049/.061 engines have excellent power, and that can allow longer lines to reduce flier RPM, as well as greater model speed. ALL things aerodynamic improve with more airspeed!

I have used the tried and true Mark 1 Eyeball method of shaping soft wood into an intake bore reducer, mounted props on backwards, added head gaskets / spacers, and almost never wanted to totally rebuild a front end to suit an oversize engine, whatever its power output, but I can guarantee that putting a Hornet, TeeDee, Shriek, or Wasp on a small plane like a Little Jumping Bean may call for all of those.

Of course, I have also mounted a K&B GH 19 on a Flying Clown, a Junior Flite Streak, and even a Junior Ringmaster. When I was 15-16-17, I really liked going FAST. Generally speaking, after the earliest years of really underpowered 05 to 09 engines, I eventually was turned off of little planes. the perpetual WIND just about everywhere I've been contributed to that impatience with the small stuff, as did Roy Cox's RTFs.

My poor experience with Sparkies befiore the 049s / 099s is why I stopped at 46s for a very long time when 51s and 60s got so popular in stunt . . we are the sum of our experiences, and whether it was my fault or not for not finding out what the spark advance / retard was all about, the sparky 60s were all dogs to me.

Lou,

I'm betting you meant "Thermal Hopper". Remember the Space Bug came out first and had the same powerful front end as the Thermal Hopper.

George

Yes, the Spacehopper is a beam mounted engine with rear intake similar to the Thermalhopper. On a Baby Flite Streak, I think an on the inside of the nose tank, or a bladder in the wing, would be necessary. I have a Spacehopper that I plan to fly some time.

I tried an almost similar project some 20 years back. Main difference was that I installed an Enya .09 (an old one with the exhaust on the opposite side to today's engines). So that you may profit from my errors, here's what I did.

I installed maple bearers with 1/32 ply extending back on both sides to just aft of the high point of the wing. This extended 2 1/4 inches in front of the wing for mounting the engine. Clearly there was insufficient room between the engine and the leading edge for installing a tank so I placed this inboard from the engine. A wheel was installed close under the engine. This mandated hand launching but would allow dead-stick landing. I figured that this engine & wheel placement would allow the fuse to remain at the original length without having to add a ton of tail weight. Minus engine and tank (but including a fuse repair) it now weighs in at 6 1/2 oz.

Though it flew tolerably well on 40 ft lines, I'd not say that it was a resounding success, never tried longer lines. I mentioned a fuse repair. I don't recall detail on exactly how it happened but the fuse did break at the rear of the wing, directly in line with the tapered trailing edge. Possibly some error when inletting for the wing.

Best of luck.

Make sure you have plenty of reeds.
Plastic one lasted longer and make less power than brass.

Brass reed, 40%, 5x4 = about 3 runs max per reed. FAST.

David

Yes. At the time frame when George Aldrich designed the Flite Streak series there was a LOT of engine development going on, mostly because of speed and combat. The Flite Streak was originally designed as a combat plane (combat was evolving rapidly too). Although it quickly was surpassed as a combat plane, it remained a VERY popular sport plane...and still is today.

I would suggest a relatively flat prop to keep the speed down...something like an APC 6x2.

Good luck.

George

I think a Flite Streak won Slow Combat at the Nats within the last 10 years, maybe came in second.