Compare Brodak 40 with Double Star 40?

What are the strengths and weaknesses of each? Weights? Power? Ease of operations i.e. 4/2/4 break? Comments?

I have one of the first batch of the Brodak 40's so I can give you half of the perspective you're looking for.

The Brodak is a great engine! Easy starts, good quality, very simple operation. It is a drop-in replacement for the OS 35s I had been using which was a plus for me.

For comparison, the DS 40 is a replacement for the Fox 35 which may be a plus if that is what you're replacing. Weights are similar, with both less than 7 oz. The DS venturi seems very small and one of the local engine gurus opens it up some. Without the mod, the Brodak has superior power. With the mod, they seem to be about the same.

When they are available, the Brodak is $50 cheaper, so that may also be a decision maker.
Steve

I've got a DS 40 so maybe I can provide a bit of insight onto the other half....

I would consider the DS 40 a niche motor. It was designed purely as a drop-in replacement for a Fox 35, and the design objective was to create a modern motor that had the same power as a good unmuffled Fox 35. The advantage was you had a quiet muffled motor instead of a noisy shaking one. The playing field has changed a bit with the Brodak 40 coming out, and I would primarily consider the DS only for planes that used to use a Fox 35. It is a perfect bolt in fit for the Fox, which makes it nice for retrofitting classic jobs, and you get much better fuel mileage and less vibration. You get to use 20% total lube fuel, which means less castor mess.

I have flown an identical plane (Brodak Mauler profile) with both the Brodak 40 and DS 40. I couldn't tell the difference in power from one to the other, but the Mauler is not a severe test on either motor. I got my DS 40 to replace a Fox in my Nobler, but I decided I liked the motor so much it was a good excuse to build a new Nobler around it.(that and the fact that the DS cylinder is taller and would not fit the existing cowl without hacking it). When and if the Brodak's become plentiful, they would get my nod because 50 bucks cheaper is significant, but if you want to replace a Fox in some existing classic job, the DS makes it pretty easy.

I didn't read all your original post. The DS is a bit lighter than the brodak, and comes with a lighter muffler. The DS will run a nice 4-2-4, it will run a constant wet two if you want, too (at least mine does) starts much more easily than a Fox, especially hot. The Brodak will 4-2-4 but seems happiest in a constant strong four, if you needle it to a strong break in maneuvers it seems to fade, like it would rather stay in a four. I have heard that the Brodak crank and port timing robs it of top end power, which is what the band-aid fix of drilling the muffler tries to improve. But drilled muffler or not it has at least as much power as the DS and probably much more whatever mode you run it in. The Brodak may not be as strong as a well-tuned FP-35 but it beats a Fox easily and is very light.

regarding adding holes to the Brodak muffler, one of the orginal development team told me that reducing backpressure by opening up the muffler slightly speeds up the 4/2 break. The motor is supposed to come back off the break quicker. It doesn't have any effect on overall power.

Phil,
Any idea if opening holes in the tongue muffler has the same effect?
Steve

At the risk of going commercial - (Not sure about this but see others do) - How about adding my Rustler-Merco 40 to the list? 8.75oz. inc. muffler. Fits OS FP and LA mounting holes. 2nd at U.S. Nats '02 Classic, 3rd at VSC '03. £92 inc. airpost, (approx. $148). Can take cards. e-m for list of about 20 vintage repro and dedicated c/l stunt engines. [email protected]

>At the risk of going commercial - (Not sure about this but
>see others do) - How about adding my Rustler-Merco 40 to the
>list? 8.75oz. inc. muffler. Fits OS FP and LA mounting
>holes. 2nd at U.S. Nats '02 Classic, 3rd at VSC '03. £92
>inc. airpost, (approx. $148). Can take cards. e-m for list
>of about 20 vintage repro and dedicated c/l stunt engines.
>[email protected]
I'd sure like to hear more about the Rustler -Merco .40 engine!

Happy users?

Unhappy users?

Tell me more!

I believe Ted Fancher and Brett Buck have experience with the Merco 40. Brett wrote some about it in a recent issue of SN, too. They liked the motor.

I have been running the Rustler Merco40 in a Zilch X. I had a ST/35 and a DS/50 in it and the Rustler ran the best and has about the power of the DS/50. I even ran the same prop on the DS/50 and the Rustler for the test, a thin BY&O 11x5. That is not the best prop for the Rustler but the motor turned it well. The up line broke and so did one crankcase lug. Part is on order and I have a second Rustler waiting for my Tucker Special to get done.
Ed Ruane

Several years ago I purchashed two Merco engines from Hobby Lobby. A .35 and .40 UC. I was happy to see new stunt engines available. My joy was short lived. The .40 had bad cylinder gasket. Hobby lobby sent a new gasket with no holes for head bolts! It started ok and seem to run decent. I put it in plane and it would run good for two minutes then fade, then run good . All the time with good fuel. Compression was low. The .35 was better,but I passed on it and sold both. The Fps were much better. They are heavy with muffler. If you need to spend $148.00 for modified engine I would get a DS.40. They are excellent. The Brodack .40 looks good, but has massive muffler. So bang for buck the BrodacK is way to go. If you like your self and have the money DS.40 is the one to get. The tounge muffler for Fox/Fps/DS.40 will fit all. Regards,Dan.

PS I am not saying modified Merco isn't a good engine but it is heavy compared to DS/Brodack. I hate to add tail weight after all that builing!!!!

While making comparisons, The Double Starr and Brodak 40 are made by the same company, so quality should be the same. The Double Starr is made to replace a Fox 35 and the timing is the same. The Brodak 40 is made to fit replace the OS 35S, and, as I understand it, it is more of a retimed FP. The Brodak tube muffler isn't that bad for weight, but it still copies the FP muffler in looks. There are tongue mufflers available for both which reduce the weight substantially.

All in all, the Brodak should be a stronger running motor
They should be approximately equal in weight, especially with a tongue muffler,
Quality should be approximately the same.
The Brodak is cheaper.

Let's see, recapping the above:
The quality is the same,
The weight is the same,
The Brodak motor is stronger running
The Brodak motor is cheaper.

by any act, error, or omission, I have, intentionally or
unintentionally, displayed any breedist, disciplinist, sexist, racist,
culturalist, nationalist, regionalist, localist, ageist, lookist, ableist,
sizeist, speciesist, intellectualist, socioeconomicist, ethnocentrist,
phallocentrist, heteropatriarchalist, or other violation of the rules of
political correctness, known or unknown, I am not sorry and I encourage you
to get over it.

On the comments about the Mercos from Hobby Lobby. These were not Ian Russels motors. They were made by Premier Plastic in G.B. They went bankrupt if my memory serves me.
I had the 30, 30Diesel, 35 and 40
My 30 was a great runner. It took slightly higher pitch to keep the motor in the rpm range that it was happiest at, but I used it for a full season The 30 diesel was origionally the silver case version and while breaking it in after an hour on the bench the crank broke. Hobby Lobby replaced the motor with one of the newer black coated ones but I never ran it and it sits in the collection.
My 40 ran with overheating problems and we never completed the break in process. The 35 is still nib. Dennis

PLEASE DO NOT CONFUSE ME WITH PREMIER, WHO SUPPLIED HOBBY LOBBY.

Dennis, thank you for your comments. You are correct, the Merco 35 and 40 from Hobby Lobby were the Premier Engines production. At this time I was waiting for Premier to buy me out, but somehow the money never materialised! So when they disappeared, I found I still owned a half of Merco, with the guy I had been in partnership with. He and I have a slightly different philosophy, so I now produce under the name Rustler-Merco, and he retains the straight Merco title. Some Premier engines can be good, it's just that quality varied a bit. I have an old Premier 40 waiting to have a Tony Cincotta Plasma p/c fitted. I look forward to that with interest.

LAST EDITED ON May-14-04 AT 09:19 AM (CDT)
 
Let's see, recapping the above:
The quality is the same,
The weight is the same,
The Brodak motor is stronger running
The Brodak motor is cheaper.

I have been interested in the Double Star, but think they are overpriced when you compare it with the Brodak 40.

While it's been a couple years now, a good friend bought a Double Star 40, had problems. While the issues he had were enough to have caused me to fold, he persisted. Eventually came to own four or five of the things.

Relatively serious quality issues.

Annoying operational issues.

Little satisfaction from importer.

Things may have changed since then. But from what I know today, the Rustler 40 may well be *the engine* for a great many Classic models. I am seriously considering building another Oriental next winter, and unless the situation changes drastically, it will be powered with a fresh Rustler 40.

Dan

Yep, I like my Brodak 40, and plan to purchase a Rustler 40 also!

Since this thread started, I've had some more experience with the DS 40. The motor is currently in a 42 ounce 52 Nobler. We fly near sea level on the East coast. Latest tests in hot weather, 93 one day and 85 the other test day.

The bottom line is that if you run it exactly like the instructions, it will run quite well. If you deviate, you can be in trouble. Our first session, we found that the supplied two head shims were not enough. Three head shims made it run a nice 4-2-4, but with 5% nitro it was unable to fly the plane(ie gutless). Running it in a 2 stroke gave enough power, but led to overheating issues. We did determine that it liked a rev-up 11x6 prop best.

The next session, I remembered to bring my 10% nitro sig champion fuel. This made all the difference. The motor growled around in a strong four stroke, breaking cleanly into a 2 at all the right places, and flying the plane on 60' eyelet to eyelet lines. Much more power than my Fox 35 powered Nobler.

As it builds time, I'll report any more useful findings on the DS 40. So far, it does what its supposed to....

Hey Dan!! I would certainly concour with your comments, especially with the DS 50, which has been a real pain in the donkey for me!!! Regards, Roy D

Roy, tell me this isn't the engine in the Pegasus??? the one that was giving you fits at Brodak's last year?

Hi Steve Sorry, cannot tell you the DS50 isn't the same motor, because it is the same one and gave me fits at the VSC also. Might be fine for others, but for myself, I just am real disappointed with this motor. Maybe with a smaller prop, which I haven't tried, but the recommended size is just to large for this motor--that is I don't care for the run characterists with the recomended prop. Wish I had used something different in the Pegasus--the model is worthy of a better powerplant. Regards, Roy D

Roy,

I used one of my DS 40s on my classic Harold Price Crusader at 49 oz with a CF Bolly 11x6 two blade. SIG GP 003 plug and 10% nitro, 11% castor and 11% synthetic oil. Worked great. What combination of prop, plug, and fuel are you using and how did you break in the engine?

>Roy,
>
>I used one of my DS 40s on my classic Harold Price Crusader
>at 49 oz with a CF Bolly 11x6 two blade. SIG GP 003 plug
>and 10% nitro, 11% castor and 11% synthetic oil. Worked
>great. What combination of prop, plug, and fuel are you
>using and how did you break in the engine?

Tom,
Roy may yet reply, but last year I watched TD and Roy Trantham work with that airplane over a couple of days at Brodaks. I think it ran better with Trantham's motor than Decameras, and I'm pretty sure they ran through every trick in the book. For some reason that motor seemed to want to run a hard two all the time if I remember, and if you fattened the needle it went dead rich instead. For some reason the motor/airplane package just didn't work to his liking. Maybe a reverse swap to an ST 46 is in order for that plane...

One other thing I forgot to mention, DS do not like muffler pressure. They are strictly atmospheric venting only. I have a uniflow tank with the uniflow vent pointed in the relative airflow and the overflow capped. Works fine with every DS I have. What is Roy doing?

If you're saying the Double Star should be "as good as" the B-40, then that assures me that I will never buy a Double Star, after two less than desirable experiences in a row with the B-40, unless someone is RE-checking them after they arrive in this country! OBVIOUSLY NOT HAPPENING ON THE B-40. Yeah, I'm REALLY ticked! See my latest entry to my post entitled "B40 Question..." on the main forum.

Craig,

I will reiterate what I have written earlier about my DS 40s (2) and DS 61 LREs (2).

"My experience with 2 DS 40s has been very positive. I use both as replacements for ABC GMA Fox 35s. Both are more powerful than the Fox and have a classic 2-4 break and use almost the same amount of fuel as the Fox. The secret, if you can call it that, is to follow Tom Dixon's instructions on operation. Those are: Use 10% Nitro, 10 to 11% synthetic oil and 10-11% castor and the rest Methanol. The engine requires a hot plug and I use the recommended SIG GP 003. Less than 10% Nitro and cold plugs cause erratic operation. I know because I tried. I am using 3 blade CF 10x6 props on both and things couldn't be better. A Bolly 11x6 two blade is even better. Finally for breakin; I followed GMA's ABC breakin instructions. Again, things couldn't be better and I highly recommend the motor. In fact, I have bought 2 DS 61 LREs for my large ships and they are the best."

I retract my statement. I think I just got unlucky.

Craig, I also posted a response there, but feel I need to make one here, also. I don't know what you problem with your first engine was. Neither do you. On the second you found a couple of loose screws and a needle valve improperly oriented. You haven't run it yet. Neither are quality control issues for parts fit, etc. Just final assembly, and something that should be checked on all engines. I haven't heard of any wide spread problem along this line, and the engines I spot checked from every batch I have received have shown none of these problems.

And I might add, as noted elsewhere, that these engines are made at the same manufacturing plant. They are of excellent quality and construction, and truly a bargain for a limited production, out of the box engine for our purpopses.

Craig,

There is a problem with the DS40 engine, it is always compaired to an FP40 or other various types of .40 engines. THEY DO NOT PRODUCE THE POWER OF A TOP OF THE LINE 40 SIZE ENGINE...............

I have several DS40's and in previous airplane installations, I would cuss them on a regular basis. They would either run hot, unsetable needle, produce no power at all or just flat out run poorly. That is until I discovered the golden rule for these engines.

You must remember that th DS40 was made to replace the Fox 35 not the FP40. The DS40 engine will run better than any fox that I own and there isn't any comparision on the quality of the engine. The DS is a good little engine.

Now for the Golden rule: I have found through my experiences that the DS40 will fly any airplane just fine, If, if the airframe is held to under 32 ounces before you install the engine and muffler. This will bring the total weight of the airframe up to about 41 ounces, + or - 1.5 ounces.

My DS40 will pull the heck out of my ARF nobler at 41 ounces without any problems. However if this engine is installed in my green box Nobler at 45 ounces, Problems abound. No power, runs hot, unsetable needle, sound fimilar?

I fly all of my DS40's with a 4-2-4 break, on pressure and uniflow, 10/22 fuel, 10/6 to 11/5 Zingers on 58 to 60 foot lines.

DS engines are fine engines and should not be over looked. They are excellent power plants, just watch your airframe weight and you should not have any problems.

Mike Clark

"Chance Favors The More Prepaired Person"

My experience with 2 DS 40s has been very positive. I use both as replacements for ABC GMA Fox 35s. Both are more powerful than the Fox and have a classic 2-4 break and use almost the same amount of fuel as the Fox. The secret, if you can call it that, is to follow Tom Dixon's instructions on operation. Those are: Use 10% Nitro, 10 to 11% synthetic oil and 10-11% castor and the rest Methanol. The engine requires a hot plug and I use the recommended SIG GP 003. Less than 10% Nitro and cold plugs cause erratic operation. I know because I tried. I am using 3 blade CF 10x6 props on both and things couldn't be better. A Bolly 11x6 two blade is even better. Finally for breakin; I followed GMA's ABC breakin instructions. Again, things couldn't be better and I highly recommend the motor. In fact, I have bought 2 DS 61 LREs for my large ships and they are the best.

LAST EDITED ON Jul-10-04 AT 06:55 AM (CDT)
 
perhaps not the place to continue this discussion but I note from other correspondence on the main forum that the DS40 has a relatively small intake area (less comparatively than a Fox 35).
Do you use the standard venturi and have you tried a larger one?
Mine was also supplied with an extea head gasget, do I need this with 10% nitro?
Thanks

>perhaps not the place to continue this discussion but I note
>from other correspondence on the main forum that the DS40
>has a relatively small intake area (less comparatively than
>a Fox 35).
>Do you use the standard venturi and have you tried a larger
>one?
>Mine was also supplied with an extea head gasget, do I need
>this with 10% nitro?
>Thanks

Mine came with two 0.010 shims installed in the motor and two extra ones in the package. I put it in one more shim for a total of three shims in the motor, and it then ran great on 10% nitro.

People do try bigger venturis all the time on the DS motors, but before I drilled out the venturi I'd try 10% or 15% nitro and see what kind of power you get.

I have stayed with the stock setup except I use an Adamisin tongue muffler that I have opened up the outlet holes and added another row inbetween the original exhaust outlet holes.

I have owned a B40 and it worked really well for me. Easy starts, no nonsense performance. Gobbs of power for a 40 size engine. Unfortunately, I have not seen anyone flying a DS40 to be able to compare. Recently, Richard Wolsey brought out his new OTS ship powered by a DS40. I was very curious and observed several flights. DS40 started easily and ran very consistently with good 4-2-4 characteristics. I also noticed that with the stock muffler, it is quieter than a B40.

I just started flying a 2Star .40 powered Profile Cavalier (from a Tom Morris kit) a couple of weeks ago. The airplane is pretty light, tho I don't have the exact numbers. The engine runs well, but I find the power isn't enough, like dangerously not enough. Ok for rounds, but nothing with corners.

An old TF paddle type 11-5 didn't impress at sea level, and an APC 10.5 x 4.5 didn't impress at 2,350'. The venturi looks small, but I'll have to remove it to measure it, and haven't got time to do that right now. I'm flying 60' eye/eye .015 braids, Powermaster GMA 10-22. No idea of head gasket stackup, but I'll check. It runs well, other than lack of umph. It bogs down in the corners.

I still have my GMA reworked DS .40. George said the compression was way too low, and GMA was not keen on high compression, so it must have been really low. Also said the venturi was way too small, and made a new one. I'll try it also, but it'll need a lot of bench time, and I'm not sure when that can happen. I'll make a new venturi or two, this weekend, but I'm looking for more ideas on props to try. They need to be wood or plastic, not CF. Our field is a bit bumpy, at best. Steve

The problem is the venturi, Steve. It is quite small for this size engine in that configuration.

A Fox 35 has a .265 bore and a .125 needle giving it a choke area of .022.

The DS 40 is essentially a bored out Fox 35.
It came with a .280 venturi but a .257 needle for a choke area of .017

If .022 is right for a low power Fox 35, how can .017 be right for a DS 40? I think they upped the venturi without thinking they were choking it down with the bigger needle. Try a .302 venturi on it and see what it does. Then you should have your power back.

On my DS40 I am using a .300 venturi with a ST NVA on a ARF Oriental. It uses 4 3/8 to 4 1/2 oz fuel using a APC 10x5. Getting very good runs with this combination.

John Christensen

When talking with a fellow competitor at a meet two years ago. he mentioned his DS .40 and tld me to bore out the venturi .006". That made all the difference in the world. I run mine on GMA Power Master, 10/22. I use an APC 10.5 x 4.5 prop, 62 eye to eye lines. Runs a great 4-2-4, uses about 1/2 to 3/4 oz less fuel than a Fox .35.

My two B.40s, I run the same, only with 11 x 5 props, GMA 10/22 fuel. They need about three to four blades of prime, start on one or two flips after 6 to 7 dry flips, then hook up the ignitor. A steady 10,000 at launch, no 4-2-4, steady lean 4 or rich 2. Some windup on my first engine, from the first batch. I found, as did many others, that the cylinder sleeve was turned off about ten degrees. Removed the head, moved the sleeve, no more problems EXCEPT they do flood easily and do not like to hot start. Other wise, I like mine.

I would try more pitch first and foremost. My DS 40 fell on its face when I tried a 11x5 rev-up, and was better with a Rev-up 11x6.

Tom Dixon is currently flying a Pegasus (same as Roy Decamera's ship from earlier in this thread) with the DS-40 turning a Bolly 10x6 three blade, and from what I saw at Charlotte and brodaks the setup works just fine. With the small venturi, I don't think the DS breathes enough to rev up with lower pitch props, conversely, it doesn't breathe enough to windup with higher pitch props.

One prop you might try is a Power Point 11x6. They look goofy, but are cheap, easily found, and sometimes they work quite well. My DS 60 absolutely loves the 13x6 Powerpoint. If the swept tips really bug you, you can sand them down and have a 10.5x6. Currently I am running a Heavily modified Zinger 10x6 wide on mine, and have also run a Rev-up 10x6 extra wide with some decent results.

Hi Guys,

Was Googling for info on the Double Star 40 and Brodak 40, specifically looking for:

Engine tests
Motor specs
Where to buy
Costs

Can anyone help?

I am not interested in mufflers as now I ALWAYS make my own, about 1/2 oz I'd say (too light to register on my kitchen scale)

Another point from way back is that one can always flatten the spray bar in the same plane as the holes with a small needle file and a steady hand. A little metal removed makes a big difference in intake area. In this way one can use "fat" NVA's like my beloved Super Tigre / Rossi types - in my opinion the the best NVA's EVER.