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Engine basics => Engine set up tips => Topic started by: Bill Barber on January 13, 2018, 09:44:55 AM

Title: Rustler Merco 40
Post by: Bill Barber on January 13, 2018, 09:44:55 AM
  I have a Rustler Merco 40 that I need to break-in but wondering about it's power level .
 Thought it might be fun to use it the RSM Warburton Tony because the original Tony used a Merco 35 .
   So looking for some advice from someone who has used the Rustler Merco 40 .
                           Cheers   , Bill
Title: Re: Rustler Merco 40
Post by: Brett Buck on January 13, 2018, 09:50:06 AM
  I have a Rustler Merco 40 that I need to break-in but wondering about it's power level .
 Thought it might be fun to use it the RSM Warburton Tony because the original Tony used a Merco 35 .
   So looking for some advice from someone who has used the Rustler Merco 40 .
                           Cheers   , Bill

    That would be an excellent combination, with much more performance than the 35 ever had.

    Brett
Title: Re: Rustler Merco 40
Post by: Bill Barber on January 13, 2018, 10:19:53 AM
    Thanks Brett , I was hoping you or Ted would step in with advice .
                        Cheers , Bill
Title: Re: Rustler Merco 40
Post by: Dave Gardner on February 13, 2018, 05:41:05 PM
Hi Bill,

I've been running a RM 40 in an overweight Nakke (54 oz!) for several years now, but it has taken a bit of experimentation to get where I want.

The original problems were a bit short on power.....and running forever on 4 oz of fuel!  (over 10 minutes at Tucson!)

I had some custom made venturis to replace the stumpy stock one, which had 4mm bore.  Jim Lee made me some with a longer throat.....about 3/4".....and upped the bore to 6mm.  I've been using PowerMaster RMA 5-11-11 fuel with good results, with up to 10% for higher density altitude.

Currently, it swings an 11-5 APC at about 9000 rpm on the ground, wet 2-stroke.  It pulls the beast around at 5.1-5.2 sec laps, flying on 62' lines.  With the extra weight, I have to fly using momentum to keep up the speed, but it still turns corners quite satisfactorily.....even the last corner of the hourglass!

I can send you a .pdf of the drawing for the venturi for the stock nva, as well as one for a conventional type NVA.

Jim probably has the drawings on file, but let me know if you'd like a copy.

Dave Gardner
Title: Re: Rustler Merco 40
Post by: Bill Barber on February 13, 2018, 08:50:24 PM
     Dave thanks for the useful information on your RM 40 . I will send Jim Lee an email asking about the larger venturi .
 If Jim doesn't have the venturi drawings I will get back to you .
                                                      Bill
Title: Re: Rustler Merco 40
Post by: Brett Buck on February 13, 2018, 08:52:55 PM
Hi Bill,

I've been running a RM 40 in an overweight Nakke (54 oz!) for several years now, but it has taken a bit of experimentation to get where I want.

The original problems were a bit short on power.....and running forever on 4 oz of fuel!  (over 10 minutes at Tucson!)

   Dave - what nitro were you running at Tucson? Near as I can tell, if you run around 10% at sea level, you need about 20-25% at Tucson to run the same way and the same run time (with no other changes).

    Brett
Title: Re: Rustler Merco 40
Post by: EddyR on February 13, 2018, 09:48:57 PM
I have two  Rustler/40's     I ran them stock for several years but got tired of the needle valve it comes with.  I mounted regular needle valve with a .292 opening and have never changed it. My first one is # oo6 so it is a pretty early one. I got it around 2003. I ran both of them for years at a fast 2-4 break 10,000+. Very little castor and maybe 15 % oil.
 After many years they got tired and hard to start. One day I took them both down and cleaned out the carbon and now they are like new again. I had one in my Brodak Bearcat and the power was OK but it needed a lot of nose weight.
 The picture I stole from the Classic page and it is my 20 year old Saturn. One of my Rustlers has been in it for 10 years. Weighs about 50 ounces but fly's it easily. Just as well as the ST/46 that was in it. The JD Falcon had Rustler /40 in it for 3 years but later I switched to the ST/46. The JD Falcon is a large plane with a long fuselage.  I use the same size venture in both motors--.292  I run 10.5-11" props 4-4.5 pitch on the Rustler. I could never get then to run in a Fox 4 cycle style run.
 Since the Saturn in now 20 years old I am going to fly it again this year. Maybe in a few weeks.
 Great motor for old classic models. Perfect in a ARF Nobler.
EddyR