Saturday, May 10, 2014

Specifications of the Turnigy TR-111

I recently bought two 11.5 HP gas engines from Hobby King. They are made by Turnigy and have the designation TR-111.

Turnigy TR-111 111cc Twin Cylinder Gas Engine 11.5HP

Surprisingly, there is no way to get any information other than on the product page. There is not even a mention of it on the Turnigy website. So, here I post information that I have gleaned from inspecting the engine myself. I planned to use these engines together to the power the same drive shaft to get about 23 HP. I picked the TR-111 engine because they were relatively cheap, lightweight (NW of 2.5 kg each), and satisfied my power target of over 20 HP.

To see it in action, check out the video from 'redsjcman' (who also has a review on the HobbyKing product page):

I do not have a video of my own yet, but hopefully I will soon.

Now, let us move on to the specifications.

First, the general specifications listed on the box:

BORE AND STROKE: 45 mm * 35 mm * 2
IGNITION: Electronic Auto Advance Ignition
PROPELLER: 26*12 27*10
SPEED RANGE: 1400 PPM - 7000 RPM
OIL: 25-40: 1 MIX (the octane number should be 93 or higher : lubrication Type of 2-cycle oil)
NW: 2.5 kg

I made measurements using this dial caliper from Harbor Freight. I use three significant digits.

ID = Inside Diameter
OD = Outside Diameter


4 x (Standoff Spacer, Bolt and Washer)

Standoff Spacer Dimensions:
-0.789" (20.0 mm) height (distance parallel to axis of symmetry)
-0.615" (15.6 mm) small OD
-0.782" (19.9 mm) large OD
-0.236" (5.99 mm) bore
Bolt Dimensions:
-0.188" (4.78 mm) unthreaded diameter
-0.328" (8.33 mm) head diameter
-0.161" (4.09 mm) minimum hex socket diameter (for 4 mm Allen / Hex key)
Washer Dimensions:
-0.205" (5.21 mm) ID
-0.471" (12.0 mm) OD
-0.041" (1.04 mm) thickness

2 x (Muffler, Gasket, and Pair of Bolts):

Muffler Dimensions:
-1.956" (49.7 mm) can diameter
-4.046" (103 mm) can length
-0.984" (25.0 mm) chimney diameter
-0.045" (1.143 mm) chimney thickness
-~3.75" (95.3 mm) chimney length
-0.384" (9.75 mm) hex key passage hole diameter
-0.591" (15.0 mm) mount rectangle height
-1.03" (26.2 mm) mount rectangle width
-0.222" (5.64 mm) mount bolt hole diameter
Bolt Dimensions:
-0.192" (4.88 mm) threaded diameter
-0.330" (8.38 mm) head diameter
-0.160" (4.06 mm) minimum hex socket diameter
Gasket Dimensions:
-0.864" (21.9 mm) overall height
-2.04" (51.8 mm) overall width


Overall Dimensions (stripped down;unequipped with mounting hardware, ignition system, etc.):
(Please note these dimensions were not taken with a caliper, but with a ruler)
-6 11/64" length (excluding small shaft)
-10 5/32" width
-6 3/4" height

Engine Mounting Plate Dimensions:
-2.519" minimum distance between holes on shorter side.
-3.049" maximum distance between holes on shorter side.
By taking the average of the last two measurements, we can infer the hole center distance.
-2.784" (70.7 mm) center distance between holes on shorter side.
-3.435" maximum distance between holes on longer side.
-2.905" minimum distance between holes on longer side.
By taking the average of the last two measurements, we can infer the hole center distance.
-3.17" (80.5 mm) center distance between holes on the longer side.

Engine Small Shaft Dimensions:
-0.391" (9.93 mm) diameter
-1.571" (39.9 mm) length
-0.173" (4.39 mm) threaded hole inner diameter

Propeller Mounting Hardware:
6 x (Bolt, Washer, Split Lock Washer)

Bolt Dimensions:
-0.191" (4.85 mm) unthreaded diameter
-0.325" (8.26 mm) head diameter
-0.162" (4.11 mm) hex socket minimum diameter
Split Lock Washer Dimensions:
-0.217" (5.51 mm) ID
-0.324" (8.23 mm) OD
-0.053" (1.35 mm) thickness
Washer Dimensions:
-0.206" (5.23 mm) ID
-0.393" (9.98 mm) OD
-0.019" (0.483 mm) thickness
Cap Dimensions:
-1.676" (42.6 mm) OD
-0.398" (10.1 mm) bore
-0.153" (3.89 mm) thickness
-0.206" (5.23 mm) bolt hole diameter
-0.919" inner bolt circle diameter
-1.328" outer bolt circle diameter
From the average of the previous two, the bolt circle diameter can be inferred.
-1.1235" (28.5 mm) bolt circle diameter

From installed mounting spacer to shaft tip, the total length of the engine would be about 8.53".

Ignition System:

Text on the metal box:
CDI Rcexl
Automatic advancing angle ignition
for gas engines      Model:A-02
Voltage-Range: DC 4.8V/8.4V
Temperature Range: -40 degrees C / +60 degrees C

If you have any suggestions or requests, make a comment below.


  1. Any idea what the width is on this engine with the spark plugs/ignition hooked up? I am thinking about using this instead of an 80cc twin engine but only have about 12" to work with so I need to make sure it will fit first.

    1. I am afraid that it is too wide, by about 3/8" or less. If you make a little groove or hole to accommodate this little extra width from the spark plug cap you would be set.

    2. Actually, I just noticed you said about 12", not exactly 12". So if you have 12.375", it would probably work.

  2. Hi I need your help. I need to know how you combined the power of two engines to make it more than 20Hp. waiting for your reply.

    1. Well hello Raj, I used multi-rib v-belts connected to a common shaft to get a combined 20hp+. If you want the two engines rotating opposite directions, you have to modify one of the engines to rotate in the opposite direction by doing a simple procedure that involves some disassembly.

    2. This comment has been removed by the author.

  3. Thank you very much for the quick response.
    Do you have any picture of it? I'm currently working on my college project in which I'm trying to use coaxial mechanism on this engine and I need some help for that. Can I please have your email id so I can send you the pictures of what I'm really trying to make. My email id is: raj,
    thanks again.

    1. Unfortunately I do not have it with me right now, and I have since repurposed the engines for another use. But when I get the chance, I can take a picture of the transmission system so you can get an idea.

  4. Can I please have your e-mail id? I need guidance for a project I'm working on.
    Thank You.

  5. Hello
    Does this by chance have a walbro carburetor on it ?
    How do you like it so far and do you recommend it .... The price seems right. Thanks.

  6. Hello. How is the engine working? Still OK? Thanks