Cox Conquest, mods and experiences.

Neat piece Kris,

Did you make it yourself?

Yes, I made it myself, I have a small combined hobby lathe and drillpress which works okey for most soft materials and a limited accuracy. The most tricky part with the extension was the inside, I wasn't able to set-up and machine it through in one go, and even had to use a dremel to finish it. Will try to get an image of the inside too.

I'm using the stock Perry carb, and it is a little inconsistent at the lower revs. I guess it is partly due to the lack of muffler pressure, but I haven't dared to drill into the pretty muffler yet. The high-end could benefit from tank pressure too I think, there is quite a big difference when the plane is held up-right.

A standard test (for me) on other .15 engines has been 8x4, and 7x5 props. The ASP .15 XLS will spin an 8x4 prop at around 15000rpm, which is okey I think. The Fox .15BB would only do about 14400rpm, while the Conquest will do a wopping 16500rpm.

The engine shown above has the first generation conrod (cast aluminium) and I haven't dared to push it very hard, apparently the conrod cannot withstand much more than about 22000rpm.

I was wondering how you joined the slots on the extension. Dremels are good for a lot of things. I did many tests with .15 size motors using 10% fuel, 7-5 M Airscrew prop and no muffler, mostly just to see which motor to use for different planes, but also to check mods that I tried like turbo plugs and crank fillets etc. The Conquest was right up there @19.500 compared to a Rossi at 19,000. I bet the Conquest would do better with a turbo head too. The Rossi had a stock head, likely a #2 or 3. The gold head Taipan was18,300, Fox BB 17,100 after removing .018" from the head button. Could not believe how big the combustion chamber was on that. I made up a turbo head for it too for that reading using a burned out Rossi insert. The ASP was 17,600 but with a new turbo head got up to 20,500 which matched the Fora!!!!. I bet the ASP would break with a smaller prop though. LA .15 is about 17,500 for comparison. My TTiger and MVVS were in the 13,500 range. Just to keep things Coxy here, the Sportsman reedy was 12,800. No TD .15 for tests yet.

I simply made the extension in a single block of aluminium, using two 4-40 screws to hold it to the engine and two M3 screws (similar diameter to the 4-40 in size but a more common thread around here) to hold the muffler to the extension. The angle for exhaust gas inside the extension is less then 45° (compared to going straight out) but I didn't manage to machine it all in the drill-press (I envisioned a nice "S-curve" but didn't manage very well) so finished the job with a dremel and some JB weld to repair my misstakes...  

Here is a view with the muffler off:

nice engine is it run beter than tee dee .15 mkll ?wat max rpm wit 8x4 20.000 ? is it good for .15 my .19 super tiger do 22k plus conquest look heavy wit its large pipe y tink y want 1 to try for my self now cox new part for it want straight tuned pipe for max power .15 conquest tee dee is mising to my colection have two sportsman .15 to upgrade

I made up a complete muffler quite a while ago that basically copied the stock one.  It is press fit together, and I tried to braze it unsuccessfully. One piece would get hot enough for the solder to stick and the other would not.  Maybe sometime I will find my stainless steel brush and tin both parts and then join them? IDK. None of my motors came with a muffler.  David 1984, yes I believe the Conquest has a bit more power than the TDs, likely even the MK 2.  Can't say for sure though as I don't have one.  The TD would be a bit lighter if you think that matters.

The Conquest is a modern schneurle ported engine and there was even a special ABC version of it too. So there is naturally quite a big improvement over the .15MkII engine, even with the muffler and RC carb:

nice chart kris yes aspeed power to weight is matter to me y like cox for it weight compare to competition now lets find weight of conquest compared to tee dee mkll rpm is just 3000 rpm les in air engine get up in rpm tee dee just gain rpm in motion wit carb fit to tee dee improvement as the conquest is alredy upgrade ??

3,000 rpm is another 15 mph with a 5" pitch prop. If you don't need it that is fine. The TD has no muffler and the throttle is a compromise like all the other older style bar machine Cox motors. An oz. of extra weight for a motor is commonly frowned on, being 30% heavier or whatever, but the total plane difference may be next to nothing, especially if the lighter motor needs extra nose weight as is common. You may not want the extra power for the plane you have, it could fold up the wing or just get you in trouble quicker. I have some like that. Fun and gets the adrenaline going, more fun when it is just slightly out of control.

Surfer_kris wrote:The Conquest is a modern schneurle ported engine and there was even a special ABC version of it too. So there is naturally quite a big improvement over the .15MkII engine, even with the muffler and RC carb:

Hello Surfer Kris
                   Thanks for posting the chart, I will save it in my docs. I have a couple of Conquest .15 that came with the perry carb and no muffler. They were used in the old quarter midget racers using a short tube header. Maybe one of this days I`ll make a plane for the ones I have.
                                                                                 Juan

davidll1984 wrote:nice chart kris yes aspeed power to weight is matter to me y like cox for it weight compare to competition  now lets find weight of  conquest compared to tee dee mkll rpm is just 3000 rpm les in air engine get up in rpm tee dee just gain rpm in motion wit carb fit to tee dee improvement as the conquest is alredy upgrade ??

I really have no idea what you are trying to say here, which language are you translating from?

My Conquest weighs 186 g. with no muffler. David would be coming from French. I think it would maybe be better to just write it in French and have it translated here separately if his phone can't do it? I can pretty much figure it out. The wife's side of the family has pretty thick accents, not French though.

Yes, well written french would be easier to understand I think...

sory for google translation y speak english good is just my ortographe is bad wat ever language y use make mistake sory for that wil try to do bether wit time as get use to it at least y can say y speak diferent langage dy y use game x box no translating y read as is it wy y understan al wat ur say wit good or bad word is worth lurning to read english hope u understand we al love model wat ever word is use

Here is a P-51 Reno racer that can be built for the Conquest .15 it was designed by Rich Uravitch and is a very pretty model. Plans are in the Outerzone. They have the plans and construction article you can download.

                                                                                                               Juan

https://outerzone.co.uk/plan_details.asp?ID=5762

Yes, any QM15 application would be a good place for the engine, but ideally one should then use the ABC version and the 1/4 pipe. I think I will use this one more as a sport engine though, as it has the weaker conrod. I have two spare rods, the same type unfortunately, but as long as they don't snap off and destroy something else, I have a backup.

OK gents-a few more points regarding the Conquest.first there are three separate versions from three separate manufacturers-first Cox, then K&B and then Mecoa. Not all the parts from these different models interchange.

how do you tell them apart (particularly the first two)-well the Cox made units have paper gaskets sealing the lower case/cylinder jacket joint, the K&B made model has copper or brass gaskets and has a serial number stamped on the lug-in typical K&B fashion. whilst the Mecoa model has a shiny case-which immediately sets it apart from the earlier two versions.

secondly-the very early models used a different P/l for the R/C model compared to the C/L-FF-QM model-presumably with different  exhaust and transfer timing....this was later dropped in favour of a single cylinder set for all versions. There were some ABC sets made-and Mecoa offered this option-though they do not seem to be doing so currently. From time to time various people have offered ABC p/l sets for the Conquest in low production runs-these usually got snapped up fairly quickly.

now the downside...the first model/generation produced by Cox used sintered iron pistons....these used to blow apart with distressing frequency and eventually they went to barstock....as well-apart from the rods getting a reputation for being weak-the crankshafts used to break crankpins fairly regularly....and more spectacularly-sometimes the counterweight cover would let go-with generally spectacularly disastrous results to the engine  FWIW I've had all of these issues happen to me personally-other than a rod letting go.  I should however point at that the engines were being used in F1C FF power-running at around 27,000 rpm on 7x 2.5 or 7x2.8 props...and flooding off to stop-so it does represent an extreme end use.

They were-by the standards of the day (1976)-good engines-and comparable ( if you got a good one)-to a Rossi 15.....but unlike the Rossi, they were a) affordable, and b) spare parts were reasonably available...    if you were really serious, you dropped a rossi 15 p/l into a Conquest-and then you DID have an engine directly comprable with a good Rossi....these soon gained the nickname of 'Cossies'.....

I have two original Cox engines and one from K&B/RJL, I think Mecoa simply ground off the protruding casting for the Cox lettering and called it theirs...

Ron Young was active on RCU some ten years ago (maybe more), offering to help with parts and even updating engines to ABC. At that time I only had one engine myself and I didn't really feel like sending it all the way to US, and back, for the upgrade. Kind of regret that know, that was likely the last chance.

Weren't the Rossi, Cox, Taipan, and Ucktkam parts interchangeable? The Taipan and Ucktkam were ABC I think. That way you could have an Uckcox.

is larger cox .40 part can be found from k&b rjl mecoa engine like .32 tink is look the same like cox .15 conquest ????

aspeed wrote:Weren't the Rossi, Cox, Taipan, and Ucktkam parts interchangeable?  The Taipan and Ucktkam were ABC I think.  That way you could have an Uckcox.

That's worth checking actually, I do have a few Ucktkam and even the MVVS .15 might work. Conrods from other .15 engines seem identical in length but I haven't found anyone (yet) that is a direct drop-in. But all it would take is a correct reamer size, I think.

aspeed wrote:Weren't the Rossi, Cox, Taipan, and Ucktkam parts interchangeable?  The Taipan and Ucktkam were ABC I think.  That way you could have an Uckcox.

yes....up to a point-they all used the standard European setup of 15 mm bore x 14mm stroke...but of course interchangeability depends on the LINER having the same OD....not the bore. As it turned out the Taipan DID take a Rossi steel p/l quite nicely-and my best Taipan turned out to be one of these....though i only found out in subsequent conversation with the previous owner. The Taipans were NOT ABC however......so any examples with an ABC p/l would have had this swap done to them

You may be right regarding the Ucktkam -I have a Russian Typhoon ABC p/l set that certainly fits into a Conquest case....I'd need to ream or bush the big end to get the rod to fit though....I forget which way round it was-I haven't looked at it for at least 25 years....