Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Aug 03, 2006, 06:27 PM
Drydock Captian
Massey's Avatar
Spanaway, WA
Joined Jul 2006
1,438 Posts
Build Log
Conversion: Imex Toyama

After reading about P. Tritle's Bahrain I wanted to build one of my own pool ships. I love container ships so I chose the Toyama from Imex. The hull is one piece with the outer prop skegs that need to be glued in place. This ship is a triple screw hull but I am only going to power the center prop. I need a little help with the prop tho I dont know how to make them and I dont have access to a lathe for bushings for my stuffing tube. Other than that the build is going well. I have assmebled and painted the parts that can be built now and I have more there to build as well. The servo for the steering and the linkage is done and tested all is good there. I am not sure if I am going to canabalize a servo yet or get a small motor for a helichopter tail to power this ship. Servo needs no ESC but only one speed, the ESC gives me many speeds but more stuff and weight. I guess I will just have to play that part by ear when I get a prop and shaft for it. Well here are some pics of my progress so far. Let me know what you think about the little ship.

Massey
Massey is offline Find More Posts by Massey
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 03, 2006, 07:35 PM
Drydock Captian
Massey's Avatar
Spanaway, WA
Joined Jul 2006
1,438 Posts
Well I remembered that I have a Tamyia Bismark that had some props for motorization so I stole one of them for this boat. I am not going to use a stuffing box right now. My propshaft rides in the tube snug and I added a little oil to help keep the water out. I hope this will work. Now I just need to figure out a motor for the boat then most of the hard stuff is done. I will keep you all informed

Massey
Massey is offline Find More Posts by Massey
Reply With Quote
Old Aug 03, 2006, 09:41 PM
Grumpa Tom
Kmot's Avatar
United States, CA, Los Angeles
Joined Sep 2003
22,905 Posts
Wow, you are moving right along! It looks good! How long is it?
Kmot is online now Find More Posts by Kmot
Reply With Quote
Old Aug 04, 2006, 04:03 AM
Drydock Captian
Massey's Avatar
Spanaway, WA
Joined Jul 2006
1,438 Posts
It measures about 19 inches long and about 2 1/4 wide.

Massey
Massey is offline Find More Posts by Massey
Reply With Quote
Old Aug 04, 2006, 09:52 AM
Registered User
McAlester
Joined Nov 2004
1,370 Posts
How about a servo motor?
- 'Doc
LtDoc is offline Find More Posts by LtDoc
Reply With Quote
Old Aug 04, 2006, 12:39 PM
Drydock Captian
Massey's Avatar
Spanaway, WA
Joined Jul 2006
1,438 Posts
Is there any way to make a servo motor variable speed? I know I can just hook it up to the shaft and leave the potentiometer in the center so it will turn forward or back but how about variable speeds?

Massey
Massey is offline Find More Posts by Massey
Reply With Quote
Old Sep 16, 2006, 08:34 PM
Drydock Captian
Massey's Avatar
Spanaway, WA
Joined Jul 2006
1,438 Posts
Almost done

I have had this little ship on my shelf for a while and have not finished it. Shame on me!! My club has a pool out in a park this weekend and I thought this is the perfect time to take this little guy out. The only problem is that it was not done yet, so I fixed that problem.

The servo motor was too weak to function unless it was lined up perfectly to the shaft and that was getting a little hard to do. I would shave the mount down perfect and it would work good as I pressed it into the mount but after I would glue it the motor would bind and not work again. I solved this by using a tail rotor motor from one of those little indoor helichopters. The motor gets hot pretty fast but I can get about 5-10 minutes before I have to let it cool. Tub trials went great and tomorrow I put it in the pool for some real trials. (if the rain stays away)

Comments always welcome.

Massey
Massey is offline Find More Posts by Massey
Reply With Quote
Old Sep 16, 2006, 09:49 PM
Micronaut
Palmdale, CA
Joined Dec 2005
120 Posts
Quote:
Originally Posted by Massey
Is there any way to make a servo motor variable speed? I know I can just hook it up to the shaft and leave the potentiometer in the center so it will turn forward or back but how about variable speeds?

Massey
Massey,

By default, the servo motor speed is fully proportional forward and astern. For future reference, it appears (from your photographs) that what caused the servo motor to be inadequate, as well as that is causing the current motor to heat up is the length of the stuffing tube you are using in contact with the prop shaft. It appears that about 6" (?) of stuffing tube are in contact with the shaft. I had the same problem on one of my earlier micro R/C boats, and since then make every effort to minimize the bearing surface between the two. No amount of lubricant that I know of will overcome the heat loss. I use a 1/8" brass tube, with short 3/32" "bearings" either soldered or JB Welded into either end. For a shaft, I use a 1/16" piece of perfectly straight piano or other hard wire. Total surface in contact between the shaft and the stuffing tube is less than 1/2". See diagram enclosed. My motors (converted standard servos, $7.99 specials) run until the electronics die, provide adequate power for most scale speeds (except speedboats) and last about 25 minutes on a battery charge. Alkaline AA batteries last about 4 times that or longer.

I've built the Toyama before as a static model in her Scan Dutch livery. Neat kit! Looking forward to more shots/sea trials!

ERic
Micronaut is offline Find More Posts by Micronaut
Reply With Quote
Old Sep 16, 2006, 10:40 PM
Drydock Captian
Massey's Avatar
Spanaway, WA
Joined Jul 2006
1,438 Posts
Micronaut,
I would have done the stuffing tube your way had I access to a lathe and some nice dril bits. Well I have the drills but not the lathe. I used what I could get away with and I think that I will be OK. Yes the resistance in the shaft is causing more load than a bearing setup but I cant fix it yet. (A hobby lathe is on my wish list). Thanks for the input on the shaft.

Massey
Massey is offline Find More Posts by Massey
Reply With Quote
Old Sep 17, 2006, 12:17 AM
Micronaut
Palmdale, CA
Joined Dec 2005
120 Posts
Massey,

I just use of-the-shelf hobby store supplies: K&N tubing works fine, and I've used a file before to cut it. I think it may also be K&N that makes the piano wire/spring steel I use for the shaft. No lathe needed, but I gotta agree with you, a nice one is definitely on my wish list!

ERic
Micronaut is offline Find More Posts by Micronaut
Reply With Quote
Old Sep 17, 2006, 06:35 PM
Drydock Captian
Massey's Avatar
Spanaway, WA
Joined Jul 2006
1,438 Posts
Finished and maiden voyage pics

Its finished now and the maiden voyage wend good. My Toyama was the smallest boat at the outing my club had and it also drew the most attention from the club members.

On the water the ship is really hard to get balanced right. The slightest change in the battery's position will make the ship look like it is listing 20-30 degrees. Once the batts are in right the boat rides nice and handles good. The motor did get really hot after about 10 minutes of running and actually would not run any more. After about an hour of sitting I tried it again and it did work but I think I may have hurt the motor a little. I think I will look into making bushings for the shaft and use a smaller diameter shaft and see if that helps any. For now tho I am happy with my little creation. My next step with it is to find lettering and what not to make it into a Hanjin ship. Comments always welcome

Massey
Massey is offline Find More Posts by Massey
Reply With Quote
Old Sep 17, 2006, 07:32 PM
"day ain't over yet-"
der kapitan's Avatar
Western N.Y. winemaking country
Joined Jun 2005
9,739 Posts
Micronaut said:

"Massey,

By default, the servo motor speed is fully proportional forward and astern. For future reference, it appears (from your photographs) that what caused the servo motor to be inadequate, as well as that is causing the current motor to heat up is the length of the stuffing tube you are using in contact with the prop shaft. It appears that about 6" (?) of stuffing tube are in contact with the shaft. I had the same problem on one of my earlier micro R/C boats, and since then make every effort to minimize the bearing surface between the two. No amount of lubricant that I know of will overcome the heat loss. I use a 1/8" brass tube, with short 3/32" "bearings" either soldered or JB Welded into either end. For a shaft, I use a 1/16" piece of perfectly straight piano or other hard wire. Total surface in contact between the shaft and the stuffing tube is less than 1/2". See diagram enclosed. My motors (converted standard servos, $7.99 specials) run until the electronics die, provide adequate power for most scale speeds (except speedboats) and last about 25 minutes on a battery charge."

Hi Eic, Massey,

I've used the telescoping tubing stuffing box on small R/C models for many years now, and have never had any problems. I follow pretty much the same method as decribed by Eric, the exception being that I use 1/16" stainless steel for the shaft.

Thank you K-S Products for your very wonderful brass tubing---.
der kapitan is offline Find More Posts by der kapitan
Reply With Quote
Old Sep 17, 2006, 08:32 PM
Registered User
Madison, MS
Joined Oct 2004
2,451 Posts
der kapitan, I agree with you about the excellent quality K-S Products tubing; very useful stuff, for stuffing tubes and other uses.
jeepers1940 is offline Find More Posts by jeepers1940
Reply With Quote
Old Sep 18, 2006, 08:04 AM
Registered User
P. Tritle's Avatar
Albuquerque NM
Joined Oct 2003
8,463 Posts
Massey, On these small models where space is at a premium and weight is a real concern, I take the servo motor out of the burned up servo and wire it up to an ElecrtriFly 7 ESC w/ BEC. The ESC is tiny, wieghs WAY less then the servo, and sells for just under $20.00. The only down side is that it's forward only. If you want reverse, stay with the servo.

PAT
P. Tritle is offline Find More Posts by P. Tritle
Reply With Quote
Old Sep 19, 2006, 05:04 AM
Drydock Captian
Massey's Avatar
Spanaway, WA
Joined Jul 2006
1,438 Posts
Pat,
I used a Novak Micro GT ESC in this boat. Like the one you mentioned it is smaller than the servo that I used to run the rudder with. This ESC has forward and reverse and works great for this model. The price is a little more than $20 but I had it laying around from one of my not built R/C cars.

Massey
Massey is offline Find More Posts by Massey
Reply With Quote
Reply


Thread Tools