Help with Miss GEICO that is stock want to make it go 40mph.....

[16.luca]

looking to get 40mph with my stock MG.

i have 4s (2x2)(7.4v each one) 30-40c ratings

stock 1500kv motor

stock 45 amp esc

stock prop but will upgrade if need be. was looking at the Octura X645 but will this be ok for my electronics? (make some recommendations plz.)

My goal is 40mph and still having my motor,esc,batteries at a good temperature.

any suggestions are helpful.

plz be as detailed as possible i love details.


thank you guys


ciao luca.

[Rumdog]

Try a m445 or a x642

[16.luca]

would x645 be to much for my stock electronics

[16.luca]

could you tell me the speeds for the m445 prop?

[ron1950]

my geigo with a t120 and a 1800kv motor and m445 is about 45 maybe more depends on the wind conditions.....btw ose got m445 s and b in today

[16.luca]

I'm trying to utilize the stock electronics because i don't have extra money to spend on esc, and motor......

would the x645 prop be to much for my mg electronics?

[ron1950]

id not try a 645 ...it will prob cause alot of heat.....id go 442 or 642 myself

[16.luca]

do happen to know the stock specs for the stock prop that comes with the boat

[16.luca]

are your talking about the x442?

[lyndon915]

My boat, all stock with an M445 on the standard 4s was consistantly hitting 40-40.5 on my GPS. I did however melt a few bullet connectors off the motor and had to change them.
Good luck with it.

[16.luca]

when you say your boat you obviously mean your miss gieco?

btw how are you battery placements inside I'm trying to figure out how to get rid of the bounce?

thank you

[lyndon915]

Yes, it is a miss gieco. I have foam in both sponsons and my batteries hang over the front of the battery trays about an inch they are turnigy 5000Mah. I also mount my garmin GPS in front of the motor. My strut is flush with the bottom of the ride pad at a slight up angle. As far as the bounce goes, I thought I had it kicked for a while but lately it has come back. I think it may be that the bushing in my strut is starting to wear out and allowing excessive play in the prop and prop shaft. I have since burned up my motor due to clogged water inlet and replaced it with a Feigao 11XL and Etti 150 amp esc I had lying around. Speed now is around 43 but everything is running much cooler.

[16.luca]

cool.

i have only run my mg for 2hrs total i just got it.

i thought the cog was about 9in from the transom? why add more weight to the front? don't you want it to balance?

i have turnigy 5000mAh but are they 30c-40c like they say on the sticker?

btw what does changing dimeter do for a prop.

what do you think of the prather s220? good choice?

[lyndon915]

So I have a theory about the CG on this boat. Now I could be totally wrong with this but I have been running my boat in this manner and all seems to work well.
I have always read that the CG should be roughly 1/3 the length of the boat starting from the back of the boat. Now with this boat the overhanging part of the transom is a few inches long but once the boat is up on plain has relatively little contact with he water. Due to this fact I don't think that the CG should be measured 9 in forward of the transom but rather 9 inches forward of the back of the ride pads.
If you measure the length of the wetted surfaces of the boat it is approximately 27 in., 1/3 of this distance is exactly 9 inches. If you measure the total length of the boat is roughly 30 inches and 1/3 of this is exactly 10 inches.
Therefore, I believe that the manufacturer decided the best CG by measuring the length of the wetted part of the hull. This also seems to be backed up by people's practical experiences. I think that there was just a mistake in communication between the people who tested the boat and the people who made the instruction manual. Once again this is only my theory on the matter but my boat seems to be running very well like this with very little bounce and pretty good top speeds when it was stock, ie. 40+ mph.

As far as the batteries go I believe that the first number is the constant C rating and the second is burst. I'm running the 40C constant batteries. By going to a larger prop you should increase your bite on the water but you also increase your current load on your motor and ESC which can cause high temps and possibly burning something up. I have no experience with the prather s220 prop but I'm sure if you look around you will be able to find someone who has used it.

Hope this helps.

[16.luca]

@ lyndon915 thank you for the info, i think i will call probate up and ask them how they want the cog set up not his boat form either the transom or the ride pads, i will let you know what i findout.

btw how did you have your strut placed?

[HYDROJERRY]

put your boat flat on a table with just the prop hanging off the edge,, your boat should sit flat and your strut should also sit flat touching the table,,that is 0* angle then you can run your boat and adjust it from there if you want to,, i run mine stock with 2x 5000 40c lipos with the strut at 0* angle on a x442 prop and i have the offset rudder setup and it GPS's at 38.6mph with just alittle hope from little wakes.. i have my batteries even with the front edge of the battery trays..

[16.luca]

i pm'ed you hydrojerry

[HYDROJERRY]

well i hope the info helps,,i have orderd a m445 for mine i hope to have it before the weekend if so ill try it and let you no how it goes,,,

[16.luca]

is that detounged or not?

[16.luca]

you going to try with stock electronics?

[HYDROJERRY]

yes, ill probly email a freind of mine and ask him for sure first but yep,, well if i get it in time and have enough time to sharpen and balance it...

[16.luca]

ok thx

[16.luca]

would the m series be detounged or the x series?

how to i tell if one is detounged or not, maybe post a pic of one that is detounged and one that is not?

[lyndon915]

The M series is de-tongued. Hold your new M445 up next to your X442, you will see the part that is missing. I would post pics but don't have any more x series props. With the M445, make sure that the prop will clear the rudder strut and also keep an eye on your motor connectors. I de-soldered one the first time I ran mine. Upgraded to 5.5 mm connectors and never had a problem again. Also remember that if you are changing the connectors on your motor to never cut the motor wires. Always un solder them and solder on new connectors. The motor wires are always coated and you will never get a good connection again if you cut them. My boat, all stock, was getting 40.2 on the m445, you should like it. Let me know how it runs.

[16.luca]

@ landon915, first you said: "My boat, all stock with an M445 on the standard 4s was consistantly hitting 40-40.5 on my GPS".......(did you borrow one from a friend to try?) When you say "my boat" in this post do you mean your Miss Geico?

sorry i read somebody else's post and thought it was from you.

[lyndon915]

16.luca,
Yes this is a miss geico I am talking about. I believe I said that in post 12 and any reference I make to "my boat" can be assumed to be a miss geico in this thread since it is a miss geico thread. I also am not the one that said that I ordered an M445, that was HYDROJERRY in post 18.
I have ordered a M545 and M645 and hope to try them this weekend. I would not, however, recommend that you try either of these props on stock electronics.

So a quick synopsis of all of this is that you can expect 40 mph out of a M445 on a miss geico but not much more. I would not run a much larger prop without fear of damaging your electronics. Since I already blew my stock motor and am now running upgraded ESC and motor I am going to try some larger props and see what happens. The motor I have is only a 1577 KV and since I am still running on 4s I am going to try more pitch and see if I can get a little more speed out of it that way.

[16.luca]

Cool, i will buy a M445 prop balanced and sharped asap.

i have a SV27 motor 1750kv what prop would you recommend with that, i was planing on switching out the motor?

[16.luca]

btw i have setup my boat with the stem parallel to the ride pads, i put it on the table with the prop hanging off and let the stem sit flush with the ride pads.

to set up my cog my father said that the cog should be 30% from the whole length of the boat because even after its on plane the stern and the transom still hang over the back of the boat and effects the cog, he said that if i were to set it up as you tried then i would have the stern and transom not accounted for. so we measured 30% of the length of the boat and that is exactly 9in. it just so happenes to be that the horizontal piece of brace just in front of the motor mount is 9in. So we ended up moving the batteries all the way back as far as possible and we need to add 2oz of weight all the way back of the transom.
we used a rod and placed it under the boat at 9in and it seems to be on the brink of going back and forth right there over the balance point. when i put in the water the back of the stern and transom are half way into the water and the rudder is submerged. I picked it up to simulate being on plane cause i was in my pool and when i was on the riding pads the prop is exactly half way out of the water.

ill post some pics soon. so you get an idea.

[16.luca]

i was looking at the real miss gecko and they have the stern and transom half way as i do. that was my fathers reason why to set it up like that.

[lyndon915]

Your right that the COG is affected by what is hanging over the back of the boat. However that part of the boat is not in contact with the water once the boat is on plane. You can set up your CG with the batteries to the rear and weight added to the back of the boat but it is against what just about everyone is doing with a miss geico, I can almost guarantee you that the boat will porpoise badly. Most people run their batteries forward if not hanging off the front of the battery trays and some even add weight to the front of the boat. This is all in a effort to keep the boat from porpoising and reduce the chance of blow over at speed.
I don't know if you fly RC planes but they need to have the CG set very precisely as well but you don't just say set the CG at the midpoint of the plane or the back ect ect ect. You set the CG at roughly 1/3 back from the leading edge of the wing. This is different depending on wing shape but 1/3 is the general rule. Now there is a significant portion of the aircraft that extends in front of and to the rear of the wing but you do not take this into consideration when balancing the airplane, you only consider the part that will hold the airplane up.
I believe that RC boats are similar in that you should only take into account the portion of the hull that will be in contact with the water and not parts that overhang but do not contact the surface of the water when the boat is running.
Now I could be completely wrong on this but all of my testing with my miss geico seems to support such a theory. If I move the batteries rearward the boat will porpoise badly and blow over at speeds as low as 40 mph. If I move them to far forward the boat seems to run wet and slows down. The optimum position that I have discovered is roughly 9 - 10 inches forward of the bottom of the ride pads not from the overhang of the stern. Any more rearward and the boat will porpoise very badly.
If anyone has any evidence to the contrary I would love to see it but I just can't seem to find any great info on balancing a boat with overhangs.