Akula, Projekt 971, Engel - 1st test

[libor]

My subs first big water test]http://www.subcommittee.com/forum/IMG_5466.jpg[/img]





Libor



Edited By libor on 1159253871

[KevinMC]

Looks great! Tell us more

Looks great! Tell us more about what the photos do not- how did it go?

(And what happened to the bow planes?)

[libor]

This was first test in

This was first test in a pool without proper prior trimming. The submarine model is AKULA type modified kit from Engel. I use FX-18, European 40MHz frequency with 8 channel Robbe-Futaba receiver.



I read in this forum once that Engel subs have big turn radius, therefore I installed bow side thruster. And now I can confirm, that turn radius without thruster is really biiig. Just on rudders I will not be able to turn around in that 10m pool. Luckily I found out that thruster in bow did really good job, in slow speeds I am able to turn that 1,2m long sub virtually around its axis. People here prefer to install the thruster in the aft, however I had no space in aft so I installed it in the front but result is still good and satisfactory. I can only recommend to install side thrusters in big subs.

Another thing is again confirmation of knowledge I got from this forum before. It says that you should not put all the lead weight that manufacturer says to should put inside your sub. I put barely the half of recommended and still I found that sub is heavier on its aft than it should be. This I will solve by removing few lead rolls from aft side and/or putting some polystyrene in the free flooding part in the aft.

As for diving I undertake only three static dives – went down and then up just as dream. Signal in 1,5m deep pool full of chlorine and other chemical stuff was without any disturbance. After 30min of drive I found a minor leak through badly tightened screw.

As for the power, I use six D type cca 8750 mAh NiMH batteries. Again I have to thank to people from this forum for their help while solving a problem when not all of motors wanted to work simultaneously while just 5 batteries was installed as recommended by manufacturer. Addition of sixth solved this problem. Another thing was charging. After consultation I learned that I can use my charger with time switch which switches off the charging process of these big batteries too soon to have them fully charged with a simple trick – just starting charging process again. In this test I ran for 1 hour and I still can more.



I wish to scale the sub a little, here are some pics of details.

[libor]

Finally here]http://www.subcommittee.com/forum/icon_razz.gif

http://www.subcommittee.com/forum/Picture 260.jpg

http://www.subcommittee.com/forum/IMG_5440.jpg

Finally here]http://www.subcommittee.com/forum/icon_razz.gif[/img]

[Wheelerdealer]

Nice job! http://www.subcommittee.com/forum/icon_smile.gif

Nice job!

[stark]

AKULA & ALFA Haft to

AKULA & ALFA Haft to be the sexiest boats around ! I have a SCALE SHIPs AKULA coming , so soon I can build one too ! Very Nice Boat you made Sir !! Brian



Edited By STARK on 1157500350

[libor]

Last time I did not

Last time I did not mention about the bow planes. At time the first pictures were taken, bow planes were under construction. Now I have finally installed them.
As many things on this kit I had to make some modification in order to make it look similar to the real thing. I made them under angel and added small surfaces at the end. I guess pictures will tell more.







Now I am back in the bath and testing and trimming and testin and trimming...





Libor

[herrmill]

Very nice work Libor!

Very nice work Libor!

[sam reichart]

beautiful model Libor....thanks for posting

beautiful model Libor....thanks for posting the pictures and sharing.

[sub-nut]

nice boat libor how about

nice boat libor how about some shots of the bow thruster installation, i just got the Engle Gato kit and was thinking the same installation in her ,as i also have heard the turn radius is large

thanks and keep diving

John

[libor]

Thank you for kind words.

OK,

Thank you for kind words.

OK, I will try to describe what I did.

Bow thruster is obtained from Graupner. I had to find place for bow thruster, since it is not regular part. I take care to mach it under servos of bow planes and just before bow piston.







Then I used Proxon hobby drill to make holes. First I did small hole in the middle and then slowly enlarged them to fit bow thruster. This is the most complicated part. I tried several times, whether the shape and size of holes are sufficient, but I wasn’t very keen with this, so holes in hull resulted in bigger diameter then intended.









The gaps between hull and bow thruster I filled with Epoxy Repairs Aqua from Bison company. Do not forget to sand tubes of bow thruster in order to let epoxy better hold on them. Just after having it glued, I carefully cut overlapping parts of tubes of bow thruster.



And the rest was adding some more epoxy to be sure it will hold temperature changes and movement. Note that I added also some lead weight to ballast sub.





Libor

[tabledancer]

Very interesting.Is the hull free

Very interesting.Is the hull free flooding where the thruster is or is it dry.If it is wet did you do anything with the pump motor to protect it from the water.I really like your boat,I just missed getting one on e-bay yesterday.
TD

[libor]

The Engel Akula is three

The Engel Akula is three part hull construction with the deck which cover lower watertight compartment as whole. Free flooding area is only above the water line. The bow thruster is installed in underwater wathertight part, so I need not to do any special measures to protect it from water. Only carefull instalation and gluing with the hull.





L



Edited By libor on 1159509785

[libor]

Actually there is a bit

Actually there is a bit of small free flooding area also under the waterline, it is in the aft. If somebody will prefer to install thruster there, in order to have even better results in turn radius in speeds (as mentioned earlier, under my experience for slow turnings is thruster in the bow 100% sufficient), then he must solve the problem with running motor directly in the water.







Edited By libor on 1159513989