Amazing revelation.....

This past Sunday after all the officials were over, Steve Fitton got his Tomahawk w/ OS 25FP back out and let several of us fly it.
I was amazed to say the least. I know it's not at the top of the "Pukey Profile" list, but this thing really would do whatever you asked of it. Flight speed was constant at all times, and always a sense of the necessary power. Very akin to a good pipe run, manuever speed wise, and it handled the site's always turbulent lower circle with no problem.
Thanks Steve!
Bill <><

Bill I gotta agree.....I built the Brodak version of the Tomohawk with a 25 fp-s and it flew extremely well.....until my brother flew it into terra firma.....

Cool little plane for not too many bucks.....well worth building in my opinion.

> Flight speed was constant at all
>times, and always a sense of the necessary power. Very akin
>to a good pipe run, manuever speed wise

My experience has been that it's *a lot* better than the average pipe run -because most people set their piped airplane up far too agressively for my tastes. Even when you are blasting along at 4.6 laps, you never feel rushed, and that's a lot better than the "toggle switch" runs you frequently get from neophyte pipe users.

If you think the 25 is good - the 20 is significantly better, at least most of the time.

>> Flight speed was constant at all
>>times, and always a sense of the necessary power. Very akin
>>to a good pipe run, manuever speed wise
>
> My experience has been that it's *a lot* better than the
>average pipe run -because most people set their piped
>airplane up far too agressively for my tastes. Even when you
>are blasting along at 4.6 laps, you never feel rushed, and
>that's a lot better than the "toggle switch" runs you
>frequently get from neophyte pipe users.
>
> If you think the 25 is good - the 20 is significantly
>better, at least most of the time.
>
> Brett

We have been getting really good pipe runs with a LOT of help from Mr. Smith, so I know what you mean about the *toggle switch* runs we would get in the past. The speed of the plane with the OS 25FP just felt so constant no matter what you did. And the circle is known for turbulence and funny air. Never had a problem. That's why I referred to the pipe run style, as compared to a usual muffler style run.

I don't know what the lap times were, but it didn't *seem* very fast at all in the manuevers. (even for an old timer like me! hahaha)

I have really been wanting to get a 20, but there just aren't any around here. I have a TF kit built lite Streak that I want to recover and put a 20 in.

I was just so amazed with my first experience with a set up like this.

I appreciate you, and Dan, putting out the word on this engine/set up.

Bill <><

>We have been getting really good pipe runs with a LOT of
>help from Mr. Smith, so I know what you mean about the
>*toggle switch* runs we would get in the past.

Amazing what happens when you follow the directions!

>This past Sunday after all the officials were over, Steve
>Fitton got his Tomahawk w/ OS 25FP back out and let several
>of us fly it.
>I was amazed to say the least. I know it's not at the top
>of the "Pukey Profile" list, but this thing really would do
>whatever you asked of it. Flight speed was constant at all
>times, and always a sense of the necessary power. Very akin
>to a good pipe run, manuever speed wise, and it handled the
>site's always turbulent lower circle with no problem.
>Thanks Steve!
>Bill <><

Bill,

I have had similar experience with my Tomahawk. Mine is from DARE Design kit but essentially the same kit as the Brodak one except that it was laser cut. It flew with a Fox 35 and handled verything so well, even the wind. I think Tomahawk is a great all around design that does not get credit it deserves.

I flew a couple of 25's last season and they're all very fine engines. I just like the sound of a fox more.

Steve's Tomahawk flies very well. I flew against him in profile and was watching the Tomahawk perform in both rounds and it was very impressive. Of course Steve is a solid flyer, but the airplane flew very well.

I would think the airplane would be great with any of the 25 LA/FPs. I have a 20FP and I can't tell any difference between the 20 or the 25FP's...they both are good runners.

Thanks for the compliments about the plane guys. Later in the afternoon, after Bill flew the 'hawk, Larry Draughn flew it. One flight, after a few test maneuvers, he put in a ripping pattern, far better then I could fly it. It was awesome to see Larry wring it out so skillfully, so quickly.

A few comments about the setup. The plane started out with an LA-25. While many have reported great results with this, my engine apparently didn't get the word. I never got a consistent run out of it. Armed with the information of Brett's Skyray setup, I happened to spot a brand new FP-25 on a table at KOI this January, with a good price on it. I then bolted this acquisition onto the plane. An APC 9x5 went on, not so much an intentional violation of Brett's suggestions but more the fact nobody around here stocked the 9x4. I used 29% all castor 5% fuel, mostly because the engine was 1) never run and 2) an older iron piston FP. I never fooled with the venturi or needle and used the stock muffler. The guys who saw it fly at Marietta this May saw the plane's second flight with that engine on it. So far,(about 50 flights later) it has run well enough I've never bothered changing anything. I suppose I should probably go to a 20% lube before all that castor varnishes it up, but I want to finish off the gallon I'm using right now.

The plane itself is a box stock Brodak kit. I never expected it to fly great, so I never bothered with adjustable leadouts or tip weight box. Everything is exactly as the plans indicated.(except the tailwheel, as the plans showed a skid and I fly off asphault.) My one trimming tool was to cover the wing in monokote so I could dewarp it if needed. No adjustment was required. I never bothered to weigh it, but since there has been interest in this plane I may try to weigh it tonight and report on it.

So in the end, its a bit of a happy accident that I have a good plane. Maybe because I was not trying too hard I didn't hose up anything in construction.

My flying partner has a flightstreak with an FP-25 on it. Its flown great on a similiar setup for ages. Now if we can just find an FP-20 we can see how much better things might be.....

>I then bolted this acquisition onto the plane. An APC 9x5
>went on, not so much an intentional violation of Brett's
>suggestions but more the fact nobody around here stocked the
>9x4. I used 29% all castor 5% fuel, mostly because the
>engine was 1) never run and 2) an older iron piston FP. I
>never fooled with the venturi or needle and used the stock
>muffler. The guys who saw it fly at Marietta this May saw
>the plane's second flight with that engine on it.

>... I suppose I should probably go to a 20% lube before all
>that castor varnishes it up, but I want to finish off the
>gallon I'm using right now.
>
>So in the end, its a bit of a happy accident that I have a
>good plane. Maybe because I was not trying too hard I
>didn't hose up anything in construction.
>
Before you give up on a good combination, consider getting to the same high oil content, but with a mix of oils that contains enough synthetic lube to keep the engine clean, inside and out.

I say this because I've noted a greater docility for a Max FP-40 that I've used some with a lot of oil, than for a similar engine I had previously. On a 20% oil content mix, with anything between 10" and 11" diameter and lower pitched than 4" seemingly not available for less than the $30-plus range (haven't priced those in ten years), for that prior 40, I had my choice of a runaway as soon as it broke to a two cycle (it flatly wasn't dropping back to a 4-cycle), starting off from the get-go in a Slow Combat rate of speed, or so rich it wouldn't break and also really didn't have adequate power.

I was running some GH Torps on a 10% Nitro fuel mix with 27% oil, made up of 11% Synthetic, and 16% Castor. For its first run, I fed the new FP 40 some of that fuel. The results were rewarding. It's much messier on the outside of the plane than mixes with less Castor, but this particular FP chugs along in a strong four cycle without any tendency to break, unless I needle it a lot leaner, and the two-cycle speed seems much more controllable, and there's much less likelihood of it NOT breaking out of the two-cycle. Right now I don't have much of a plane to use it on, but I'm pretty sure the better behavior is at least in large part due to the fuel choice.

.

Kiwi

Bill,

Excellent title to thread you have begun. Even after talking to Brett about the 20FP I was not prepared for how well they run. I've gone from having one 25FP-powered ARF Flite Streak to tossing the 25 in a corner--it will soon be converted to a 20--and quickly coming up with two ARF Streaks, a plans-built Super Combat Streak, a SIG Skyray 35 (renamed Skyray 20), all powered by 20FPs.

These models and fiddling with them has consumed huge blocks of time which otherwise shoulda, woulda, coulda been dedicated to my Oriental and two Impacts, all three needing trim work and practice time.

And Steve Fitton is doing **exactly** the right thing, what Brett has done many times in the past, what I am trying to do here in the NW, and that is to just let people fly something which appears to be nothing more than yet another Pukey Profile. But might well fly better than some of their high-zoot contest equipment.

Comments, in the order presented:

Steven, I do not wish to be harsh, but a profile whatever fitted with a 20FP has very little to do with the model itself. It's nearly *all* about the engine, the amount of power and how this power is delivered.

If your 25s were indeed performing to the standards we are talking about on this thread, you would today not be flying the Fox 35 on your Tomahawk. Fact. From someone who loves the sound of a good Fox 35, don't ya know...

Circle Burner, yours is not a universally held opinion, although certainly a credible statement as it relates to your own engines. My own 25FP will need conversion to a 20 before it is worth flying again. Just my bad luck, possibly; glad yours work well for you, especially noting that you have the 20FP to use in making comparisons.

I hold little hope that there is a suitable tune-up for the 25LA. They are nice sport motors, they tolerate a wide variety of props and fuel. But they are nothing more than a second- or third-tier unit when compared directly to a properly set up 20FP.

Steve, I am again a little taken aback that a 25FP is working for you, see above. I don't doubt you, it's just that your experiences run counter to those of my own. Well, not when talking about the 25LA...

Brett's initial use of the 20FP was pretty much an accident, you're in good company.

As to availability of the 20FPs, there are tens of thousands out there, although it is unfortunate they are no longer a standard hobby shop item. Then again, how long has it been since ST 60s were in production and nobody seems to have any trouble coming up with one if that's what they want for their PA model.

Mike Conner, our local Good Guy Engine Dude fairly quickly came up with four used 20FPs for me, one of which ended up being a parts motor. While some may laugh, knowing what I know now, I'm not so sure I wouldn't be very tempted to build one from new parts. Couldn't possibly cost more than my most recent Fox 35, in proper application would run a lot better and a lot longer than the Fox.

You guys keep spreading the word. Brett came up with the "Brett Buck Tune-Up," even the calculations to prove what we see in the air and how we are getting this style of power delivery. He even mumbled about it in Stunt News. Five years later I did nothing to further refine the setup, but was so surprised that I began yelling about it. Still am, as a matter of fact.

The next step has to be people like Steve and others stepping back and saying, "Hey, want a ride on this model? Let me know what you think."

And the step after that may be--at least it is my hope this proves to be the case--one or more of our tuners finally taking the 20FP seriously enough to actually fly the thing with proper setup, replicating same with a small-bore motor which is currently in production and so readily available.

The only difference I see between the 25FP and the 25LA is the FP has a slight power advantage. I can tell no difference in the 20 and 25FP. The only mods I make to the 25 LA is to replace the remote needle with an FP type needle.

I run Byron 10% nitro with 20% half and half. I add 4oz of castor and 1oz of Aero1. On all the above referenced engines I run a APC 9x4. Call me lucky but they all run great!

>The only difference I see between the 25FP and the 25LA is
>the FP has a slight power advantage. I can tell no
>difference in the 20 and 25FP. The only mods I make to the
>25 LA is to replace the remote needle with an FP type
>needle.
>
>I run Byron 10% nitro with 20% half and half. I add 4oz of
>castor and 1oz of Aero1. On all the above referenced engines
>I run a APC 9x4. Call me lucky but they all run great!

You are lucky, and I'm glad they run great.

There is a clue here, however. If your 25FPs are running just like your 20FPs *and* the only apparent difference between your 25FP and 25LA is the former having a bit more power, I must loop back and question the actual way power is delivered by either your 20FPs or 25FPs.

(Sorry. Could my wording be any more confusing?)

I see large differences between my 20FPs and several 25LAs being flown locally. For one thing, while a little softer in specific output, the 25LAs will readily handle a wide variety of props, from APC 9-4 to 10-4, 10-5, 9.5-4.5 and others we probably don't know about and so haven't tried. The 20FP will work to its potential *only* on the APC 9-4.

Bill, I know you know your stuff, so I'm not nagging you. But, truly, there is a consistent and repeatable benchmark out there in 20FPs run to the Brett Buck Tune-Up and I am merely interested in seeing as many of us as possible on the same page so future comparisons can be made with some degree of accuracy.

I don't run these FP jobs myself but I see Dan run his quite often & they run extreamly well.

For anybody who is interested, I weighed my 'Hawk last nite. 26 ounces.

I will keep a lookout at the swapmeets for a 20 FP. I'm more curious about this motor than ever now.....

>For anybody who is interested, I weighed my 'Hawk last nite.
> 26 ounces.
>Steve

I will add to Steven Yampolsky's comment here, I have a CLC Tomahawk
...CLC Veco version, that flys very well with a CS Oliver Tiger mkIII
.15 repro. I use .012"x 60' lines, a Taipan 8x6 in a breeze and a
Taipan 9x4 in very calm conditions. I had to build this model to
accomodate the lightweight engine(5.9ozs). The ready to fly weight
sans fuel is 20.5 ozs. I was amazed how good it flys. This shows how
the design can accomodate a wide engine displacement range. It is a
really nice sport flyer and stunt trainer.
Steve F...Your 26oz model sounds just right for a .20/.25cu"
Tomahawk.
Tony

Steve,

If you give it back I have one you can play with for a while.

Dan,
Is the 20 sleeve/piston a drop in for the 25? Are the rods the same, etc.?
Thanks,
Bill <><

>Dan,
>Is the 20 sleeve/piston a drop in for the 25? Are the rods
>the same, etc.?
>Thanks,
>Bill <><
>
>When the character of a man is not clear to you, look at his
>friends.
>Japanese Proverb

Bill,

In short, yes. While I do not have a parts list here, I am nearly positive that in order to convert a 25 to a 20 one needs piston/cylinder set, wrist pin, head, gasket set. Nothing more.

Well, one thing more, possibly. The little cone-shaped doo-dad in the mufflers of 20FPs is *required* and yet they were not typically included with mufflers for the 25. There is a listing for something called a super-silencer and I am hoping this is stock muffler with an insert. Especially annoying as while I have three running 20FPs and a parts motor, only two of my four stock muffers came with the muffler insert.

While I have no access to sales figures, I am pretty sure there were quite a lot more 25s sold than 20s. As soon as you guys get done snatching up all the 20s, a viable option is to snag 25s, converting them with new parts to a 20.

>For anybody who is interested, I weighed my 'Hawk last nite. 26 ounces.

>I will keep a lookout at the swapmeets for a 20 FP. I'm more curious about this motor than ever now.....

>Steve

Steve,

As good as the results have been with your 25, I'm predicting a decent 20, set up to the exact specs from Brett, will open your eyes. Maybe not a lot, you may be closer to Killer Profile status than I am assuming with your Tomahawk, but I am most anxious to hear of your results.

I'm fixin' to start another thread on this topic, titled "Spreadin' the Word on 20FPs."

While I am not interested in managing the way this all comes to pass, there has been quite a lot of discussion, this thread contains what I believe to be true assessments of model/engine combinations, and flying season is just beginning in earnest.