Getting ready to start building the TF DC3. I am considering using a pair of HP VT .49 4 strokes. Anyone have any experience with these engines? I'm sure most people would reccommend OS, Saito, YS, etc. The problem is, I'm trying to save a buck.

John

Trying to "save a buck" on the engines is the worst thing you can do to a multi-engined airplane.

John,

Agreed, they need to be dependable, but if you already own them & they run well, you should have no trouble. Make sure you've got an airtight fuel system as the lines are quite long from the center section tanks to the engine nacelle's. Not sure how good the fuel draw is on those motors. I've used some other HP 2strokes years back and always found them to be decent quality.

BTW, go for the scale rudder hinge. Lot's of work but it REALLY looks good!

Bob

Thanks for the input. The reason I'm trying to save a buck is I'm retired on a small pension plus Soc. Sec. Just started RC this past spring, so I don't have much in the way of supplies or experience. I was very active in control line in the 50s, 60s, and 70s, but things are a little different now.

I am buying the DC3 from av8r4aa here on RCU and now I need the engines. I have decided that 4 stroke would be the way to go. I don't think I can really afford a new OS 52 or Saito 50, and the used ones I see are hardly less than new. I found the new HP VT 49s for $130.00 each. That's $50.00 bucks an engine less.

Anyone else have any experience with these engines? How about other makes?

Again, thanks for the input. I can use all the help I can get.

An os .52 or saito .50 is way too much for the TF DC-3. I had os .40's on mine and it was still overpowered. This was at 500' ASL back when I lived in Tacoma, Wa. Hey, atleast your not building a 4 engine airplane!

A4HawkPilot:

Were those .40s 2cycle? I understand I would need about a .48 or .50 4 cycle to get the same power. I fly with the RAMS in Auburn. Our field is on W. Valley Highway in Sumner. Runway is grass, so I will be wanting a little more power on those days when the grass is due for cutting.

Thanks for the picture. I had kind of decided to use civil airliner markings.

I'm running O.S. .40 LA's on mine and it has plenty of power even with running 3 blade props.
Randy

Amen! Different, but definately easier!

Pretty much any 2 stroke .40's will power this bird easily, even from grass. 4-strokes *sound* better, but the $$$ are higher no matter who's brand you buy. For what it's worth, the O.S. LA series motors are a great sport .40, as are the Magnum's. There's also about a million used K&B .40's floating around out there that'll run forever with a new ring & bearings installed.

Welcome back to modeling!

Bob

Yeah, some of us are just gluttons for punishement.

Oh, sorry, I meant I used 2 O.S. 40 four strokers. I could have taken off in grass easy with this set up. My take off roll was very short if I jammed the throttles to the firewall. Most of the time I would take off on 3/4 to 2/3 power to make it look a little more real. I have been looking into engines for my C-130 lately. While I like the LA series, I don't think blue engines sticking out of the cowls is going to look right. O.s. does not make a silver version for the .25! I thought about 4 strokes but they are expensive and just wont sound right anyway. I think I am going to go with the FX series. They are just as reliable in my experience with them and they have that extra power.

I flew at the rams a couples times. Last time I was there was for a pattern meet. Nice field, but I used to live about 7 minutes from the big paved runway out at Ft. Lewis. You can't get much better then that!

Hi
How about the OS ax 46 s , these are very reliable and are not expensive . I ll be starting the TF dc-3 in the spring I ll also be useing something called a Twin Sync , it s suppose to be much easyer to sycronize the engines

Michel ( Mike )[8D]

Michel,

You are just like me, i am using 4x OS 46FXs on 105" WS S Connie and you are using 2x OS46AX's on 88" WS, wow we both have higher weights and wing loadings!, once i have flown my Connie and if it lands like falling brick out of sky, then i'll know engine weight is too much, i'll consider going to OS 40's maybe but till that time im using as planned......

Hi Concordefan

I ve only considered the OS ax 46s , because they are not expensive , and are very reliable . you have made me think of something . Did you know that the Saito 56 is lighter than the OS 46ax , I believe by 2oz . I have this disire need for a great sound . Roughly the price of a Saito 56 is $250 , roughly . and the sound of 2 four strokes must be awwwsum [sm=biggrin.gif] But I must consider the price , and the diameter of the props 12x6 , it might be a bit big . I haven t made any commitment yet , but I will be soon The only thing that I have commited myself to is the Twin-Sync I suppose that the engines are next . Most likely the DC-3 is in March of the comeing year . I m very interrested in youre connie , please keep me informed , 4 engines WWWWWWoooooWW[sm=thumbs_up.gif][sm=thumbs_up.gif][sm=thumbs_up.gif]

Please parden my ignorance Whats a Connie ?

Be Well

Happy Holidays

Michel ( Mike ) [8D]

Mike,

Oh sound wise you are going to love it, i flew my B25 with 2x MAG 25 2 strokes and its is awsome sounding plane, once engines are properly sync they just hums beautifully, i love that sound myself too. You are rigth of financially OS 46's are very resonable and readily availabe anywhere and are very reliable engines, one of reasons of chosing 46Fx's was the reliability of them. You will be very happy with them.

Kind Regards,
Sammy

Hi!
The HP .49 fourstrokes aren't that reliable and they are too big and powerful, and they are to heavy too.
A pair of OS 25 LA engines or OS .30 four strokes is what I would recommend.
I use a pair of OS FS.26 in my Marutaka DC-3 (span 211cm, weight 3,6kg )and these engines are perfect for it as they are very reliable and uses only 5% nitro and 15% all synthetic oil (Motul "Micro" ).

Hi Jaka

I think youre right

Youre plane looks great , this is the plane with the OS 30s , right . Is that weathering that I see on the plane , very inpressive and I also see that you have three bladed props . Have you ever had a situation were one engine has quite ? I ve looked at the weight of the OS 30s and the OS 40s , I believe they are almost the same weight and just a couple of dollers more . I also beleive that the Saito 56s are overkill . The plane would look more realistic with the OS- FS 40s and much less weight .

If I may ask ? What type of covering do you have on it ? and what is the total weight ? and do you have retracts or what type of retracts ? Youre plane looks truely scale [sm=thumbs_up.gif][sm=thumbs_up.gif]

Happy Holidays


Michel ( Mike ) [8D]

Hi!
Thank´s.
The DC-3 is covered with small strips of Oracover plastic film wet sanded on a sheet of glass then ironed to the fuselage/wing.
I use OS FS .26 and they are plenty ...the airplane nearly jumps into the air when I give full throttle.
The flying weight is 3,6kg.
I use 25-30 year old Swiss made (Gizendanner ) electrical retracts powered by a 4,8V, 400mAh NiMh battery (retract time is around 5 seconds). This battery also powers the landing lights in the wing and the tail and fin lights. Flaps are 4 piece, driven by two small Hitec 85 servos.
The propellers are my own made carbon fiber 10x5, 3-blades and my OS .26´s turn these with 9200-9800 rpm.
I use a 1000 mAh NiMH 4,8V battery as power for the reciever/servos. And I use a small JR 700 reciever.

Don't fall in the very common trap of going with too big engines...the reasoning for this is seems clear...nearly the same weight as with smaller engines...but remember that a bigger tank must be used...a bigger engine mount has to be used...sturdier construction must be used around the engine.....and so on and on. These things add weight and weight is your worst enemy in an airplane. last but not least is the fact that bigger engines has negative effects on how the airplane flies and behaves in the air.
I want my scale planes to fly "on the wing" ...not behave like a pattarn plane or a racer.
I enjoy competing in pylonracing, so I get my share of flying fast with other airplanes.

I have been very fortunate that an engine has never quit on me in flight . But I have been very carefull to set up the engines real well and I hope they will continue to run well.
Throttle action is instantanious when I give ful throttle and the engines nearly turn the same rpm at full throttle. I use two small Bluebird (10g )servos for the throttles to save weight. Fueltanks are custom made 110cc tanks, soldered tin tanks, set up with "Uni-flow " principle.
I use no silencer pressure. DC-3 flies like a big 2m sailplane and could nearly stand still in the air at idle.

crshnfix,

I too have this kit as a retirement project. I have bought all the elements while I'm still working (just another 16 months) and then I'll be in your same boat. I am going to use (already have) OS40FX's with slimline pitts mufflers so the exhaust will exit directly down and you won't have to see those ugly stock mufflers. I also have the Robart retracts that are made for this model. I'd rather have a little more power than necessary "just in case" and otherwise intend to fly this baby scale.......that's what good throttle management will do for you. If you and others are worried about overpowering this bird then you can just limit your throttle on your transmitter. I am not a fan of overpowering scale aircraft but these motors seem a good fit. I was going to try 2 Wankles, but that is just too expensive.

Cheers,
Andy

Hi!
Sorry! But too big engines like the OS FX .40 or FX .46 is going to make your DC-3 fly like a pattern airplane. The problem is weight! Low weight means you can fly it like a sailplane, slow and predictable at 1/4 throttle, without worrying about it stalling. High weight means you must fly it on power ...not on it's wing...at scale speed...making slow speed flying not as joyful. Throttle management is something which is very important when flying a scale airplane ...but having too big engines is not making scale speed flying possible or as enjoyable as the airplane tends to fly faster and have higher stalling speed.
Choosing too powerfull engines always seems to be an aspect of this hobby.

Jaka,

I chose the OS40FX's over the OS46FX's for that reason. The manufacturer recommends that size to give you options like engine out situations. I admit I'm new to twins but certainly not to modelling and I agree with you that the tendency is to over-power which is something I choose not to do. I really don't think that flying on the edge is a good idea either and like I said in a previous post, you can always limit power on the transmitter but I certainly don't intend to fly this plane like an over-powered sport plane. There are some compromises to be made here. I am building a Twinstar as a trainer and I chose two OS25LA's to power the plane because the consensus was that the plane would fly on 15's but if you had an engine out a .15 would just not be enough to maintain altitude and get you back to the field. Even the original DC2/3 had more than enough power. The airlines were used to tri-motor airplanes for transporting passengers and that is what they asked Donald Douglas to design. He came back with a twin that would do the job and he proved it by overloading it and flying it over mountains, consequently the airlines bought the idea of a twin and the rest is history. He would have never sold the plane if it was just powerful enough to do the job but not handle situations that might have arisen.

Regards,
Andy

[8D]Hi

Andy I think you are right . jaka I truely believe what you have said , fly on the wing and whatch the weight To overpower this airplane would be a mistake . To fly with two OS30 FS would be on the boarderline . In no way I m I a smart guy , if I put two OS30FS , I would be much better to kill the other engine , and come in on the wing . I have made the decidion to put in OS40 FS over the Saito 56s which is way too much power . I really want the 4 stroke sound . Ive determined that it is inbetween the OS30FS and the Saito 56 , I truely don t think that there is another option , or if thier is someone with a better idea . I d love to put in the wankels , but they are way too expensive I have at least another two or three weeks to make my decition maybe I will change my mind

Great thread .

To All A Happy Holiday


Michel ( Mike ) [8D]

Hi!
Believe me The OS FS.30 will be plenty if you build it light, at around 3.5-4kg.

Hi jaka

Thers one thing that I must tell you , I cann t stand plastic film , I detest it . I m a dope builder and always will be [sm=bananahead.gif] I know that I will be over 10 LBS I truely appreciate youre confidence in the OS30FS and you are an experiece and seasoned flyer and the weight difference is small and the fact the Top Flite DC 3 is tail heavy I would only end up adding the weight

Youre oppinion is very appricated THANKYOU [sm=thumbs_up.gif][sm=thumbs_up.gif]

Happy Holidays

Michel ( Mike )[8D]