Is my MG "special"? 30mph stock?

[PDR447]

"Special" meaning specially slow... I might be missing something but it seems that most people are running at in the low 30's(32-35) stock. My boat struggles to even hit 30. I've spent plenty of time testing strut settings and the best I ever got was 30 on GPS. I even tried a friends ESC to make sure mine wasn't stuck in LOG throttle or something.

My boat:
Hardware: 100% stock
Strut: ride pads are 1/8"-1/4" elevated when the strut is resting on a flat surface
ESC: Linear, high timing, no brake
Batts: 2xVenom 2s, 5000, 20c

The other thing is I cannot get the "WA WA WA" no matter where I set my strut. I guess that's kinda nice but I can't help but feel it doesn't "WA WA" because it's not performing to it's fullest.

Thanks in advance for any thoughts/advice.

[lectriglide]

Whats your battery placement? Mine hang off the back of the tray about 1/2".
Also is the strut neutral?

[PDR447]

batteries are flush with the back of the trays. Now that you mention it that's the one thing I forgot to try adjusting. But, I did check the CG on the boat and with the batts at the edge of the trays my CG is about 9" from the stern.

Strut, I tried various settings. Went from too high, to too low, and a couple points in between. I saw decreases in speed at either extreme. But got my best run(30.5) somewhere in the middle. I'd say the center of the shaft was about even with the ride pads.

[lectriglide]

Do you have different batteries to try. Don't think the Venoms are up to the task.

[Diesel6401]

Do you have any drive line binding?
Did you try different batteries? (Venom batts can be iffy)
Is the coupler tight and not slipping?
Do you have the proper direction flexcable?
Do you have enough of a gap between the drive dog and strut?
What are your temps on the motor & esc?
Has the motor ever been dropped or overtemped?

[Darin Jordan]

Without data, it's tough to diagnose performance issues like this. My first suspect is the batteries. You do get what you pay for sometimes, and if the batteries are dropping voltage under load, you are going to be slower. The MG should be doing around 35-37 out of the box if it's running correctly.

The "Wa-Wa-Wa" that people experience is do to setup, and, frankly, lack of speed. Once you get this hull up to speed, that part tends to go away if you have it setup correctly.

What are the condition of the batteries??

[PDR447]

Thanks for all the responses. I guess I should also mention that I bought the boat second hand. The original owner purchased everything at the LHS in December. He told me he only ran it maybe 5-7 times and I believe him as it looks brand new. Also, there's not really anywhere to run them nearby so that would make it harder to get a lot of time on it. So with that said I can't completely verify the history of the boat. He was an experienced hobbyist(mostly planes) so I'd trust him to treat it properly.

To answer your questions:

Flex shaft feels fine/free. Just greased it.
Coupler is tight.
Flex is the correct direction.
Drive dog/strut gap is 1mm as per the manual. Set using a feeler gauge for accuracy. Is this the best setup? Should I give it 2mm?
Temps on everything(batts, ESC, and motor) were usually in the 70's after a long run. 80 max
Can't say if the motor was ever overheated due to being the second owner. But it was only ever run on the stock prop at 4s. Unless the water pickup got clogged I can't see it overheating.

Now, the batteries... Seems these are the main suspect. As I mentioned they're Venom 2s 5000 20c's. The original owner purchased them with the boat. They seem to be in great condition as they charge well and stay balanced within 1-5mv at all times. I don't have any other batts I can test with at the moment but my friends have some on the way from HK so I can try those when they get here. Are Venom's really that bad? I see plenty of people running Turnigy batts with good results. I would like to believe that Venom is at least on par with Turnigy.

So I guess there's not much I can do until I get my hands on another set of batteries. Thanks again to all of you for your input! I'll update this thread as soon as I test with the other batteries.

[Fluid]

All of the power in any boat is in the cells, so substandard cells will not give top performance. OTOH you don't need the most expensive cells to get a decent top speed with the "spec" motors. I'd not use cells with less than a 30C rating, this defines the ability of the pack to deliver energy. Unfortunately many companies inflate the "C" and capacity values for their packs, particularly the "bargain brands".

Knowing that the boat has a history, other things which can cause lower performance:

- Non-standard or damaged propeller
- Over-heated motor
- Re-programmed ESC

The latter two are longshots but possible. Check the prop, if the original owner broke the factory prop he may have replaced it with a less aggressive design...or not. Good luck, you'll get it figured out.



.,

[GP73]

EDIT: Fluid beat me to it... :) And yes, figuring it out is half of the fun!

Maybe I missed it, but what about the prop?

Is it damaged or unbalanced? You might want to sharpen it at least, but you need a balancer to make sure you don't get out of balance.

Or just order one from OSE or egneg.

[PDR447]

The prop is the stock plastic prop. It looks fine with no signs of damage. I even have the second spare prop that came with the boat. I suppose I could throw that on but the one on there now looks perfect.

As I mentioned earlier I swapped the ESC already to eliminate that. The only variables left are the motor(longshot for damage there) and the batteries(main suspect at this point). I was planning on running 5s down the road but maybe I'll order another set for 4s rather than a 5s set.

What do you guys think of these: http://www.hobbypartz.com/gens.html

And what's the "dirt" on turnigy? Would they have the same problem as these venoms?

[Diesel6401]

Then Gen aces have had a lot of positive feedback. I owned a few sets of Venom batts before and didn't really care for them. The didn't seem to deliver the way the turnigy's did, that's just my thoughts with no data to back them out. Now me I LOOOOOVE the Turnigy's and is what I mostly run. I have a pair of Tenergies that are more expensive then the Turnigy's and I like them too, but for the price and knowing their performance I am a Turnigy and Zippy fan. With that being said I have had 1 pack lose a cell and 1 pack quit balancing 1 was a zippy 1 was a turnigy, but I own/owned a good bit of their packs both large and small and all I am happy with. I am using some 6000mah nano-techs and those things rock but my favorite packs are these http://hobbycity.com/hobbyking/store...dProduct=16194 best batt for the price IMO...

If you are willing to drop the $$$ Hyperions and TP would prob be the best, but if your like me and just a weekend runner by myself mostly and occasion with some friends then the Turnigy packs will serve their purpose and prob out perform the venom's.

Here's some data and you can see the difference in price
http://forums.offshoreelectrics.com/...ad.php?t=16937
http://forums.offshoreelectrics.com/...ad.php?t=17771

[GP73]

Never mind, I thought the MG came with the same stainless steel prop as the Stiletto (Prather 215).

Plastic props don't need sharpening/balancing.

I would say go with Turnigy/Zippy from HK or Blue Lipo from HobbyPartz, buy 40C or more if possible. You won't regret it.

The prop is the stock plastic prop. It looks fine with no signs of damage. I even have the second spare prop that came with the boat. I suppose I could throw that on but the one on there now looks perfect.

As I mentioned earlier I swapped the ESC already to eliminate that. The only variables left are the motor(longshot for damage there) and the batteries(main suspect at this point). I was planning on running 5s down the road but maybe I'll order another set for 4s rather than a 5s set.

What do you guys think of these: http://www.hobbypartz.com/gens.html

And what's the "dirt" on turnigy? Would they have the same problem as these venoms?

[Darin Jordan]

I've measured the pitch on all the ProBoat props. The plastic MG prop actually has a little bit more pitch than the Stiletto prop. However, it flexes under load, so I'm sure this isn't true when under power. The best you are going to see with the stock prop in a stock boat is around 34-35mph I would think. The Stiletto prop showed another 1-2mph for me... bumping speeds up around 36-37...

A 45x55 should push a stock MG over 40 without any trouble... with good cells...

[PDR447]

So it looks like I'll be ordering some new packs... As a sport boater, would you guys recommend 2 packs in series or parallel? I think I read something at some point about the pros/cons of each but I can't find it now.

The setup I'm debating:

2x 2s 5000 30c(or greater) in series for 5000mah at 4s

vs

2x 4s 2500 30c(or greater) in parallel for 5000mah at 4s

The cost of either of these setups seems about the same so that isn't a factor. Any reason to choose one setup over the other?

[jpracing1997]

I got some hobby king 5000 mah 40c packs and mine runs great. Upgraded motor and esc and now it runs 50.1 . I'm gonna reprop it this weak and break 60 i hope. I have a neu 1415 1.5y, 3s2p 5000 mah 40 c batteries and a 442 prop right now and it runs 50.