Seawind conversion
 

I live by a pond that is smooth as glass most of the time. I can fly my electric planes there with no problems and am sure I can fly an electric off the water with no problems. Although I have some brushless 3-D planes, I have never converted a Glow plane to electric. Can you give me some suggestions of brushless motors, speed controls , props and light poly battery combinations? Building this plane electric will allow me to fly it whenever I feel like at the pond near my house instead of whenever I can get to a float fly plus I love the way it looks.
Thanks for any advice in advance.
Roy
PS This will be a strictly off-the-water plane.
REQUIRES: Engine: .60 cu in (10cc) 2-stroke
OR .70-.91 cu in (11.5-15cc) 4-stroke
SPECS: Wingspan: 71" (1805mm)
Wing Area: 676sq in (43.6 sq dm)
Weight: 10.25 - 12.25lb (4620 - 5555g)
Wing Loading: 35 - 41 oz/sq ft (106-127 g/sqdm)
Length: 56" (1410mm)

RE: Seawind conversion
 

Give Kirk Massey at New Creations R/c a call. he'll give you very reliable information, good prices and quick service. Dave thacker at Radical r/c would be another possibility.

I'll be watching for more as I have my eye on the Seawind for a conversion, but haven't given it much thought. Since I already own several Maxcim motors that's probably the route I'll go. Actually Tom Cimato of MaxCim would be another good source of info.
Walt

RE: Seawind conversion
 

I had hoped to get one of the initial Seawinds for a conversion article but Hobbico wanted the first wave for glow-powered reviews. Hopefully, I'll get to start one next month.

Without knowing the size of the pod dimensions, it is difficult to make the best choice. My preference would be to use an outrunner like an AXI 5320 motor or Actro 40-4 or 40-5 depending upon prop clearance. A 3-blade prop is a definite possibility here.

RE: Seawind conversion
 

Greg,

It appears that prop clearance is going to be around 13" dia. It looks like most outrunners will be hard to use. A 3 or 4 blade Vario prop might work. The is one plane that may have to use a inrunner with a low ratio gearbox and higher rpm to get the required thrust.

Wendell

RE: Seawind conversion
 

Wendell,

Thanks for the information. I suspected as much and wanted to make suggestions with caution until I actually have one in my hands.

The geared Kontronik 600 brushless motor would work well here since the gearbox is in-line. I don't recommend using the 600 Brushless Set that comes with the Jazz-55 ESC thought due to the over-current shutdown kicking in prematurely around 45amps. I have had great success with this geared motor using a 13" prop with a Jeti 77-amp Opto ESC and a 6s or 7s Lithium pack of Kokam 3.2AH cells.

The [link=http://www.hobby-lobby.com/jetibrushless.htm]Jeti Phasor 45-3[/link] motor may work as well. On a 4 to 5 cell Lithium pack you could use an 11" or 12" prop. A 5s pack at 50 amps burst would provide around 900 watts.

Ideally, the more expensive Kohler Actro 40-4 would be perfect due to its thinner profile and near 2000w burst capability but Hobby Lobby is discontinuing sales of this motor due to its high price.

RE: Seawind conversion
 

76,If you haven't bought the Seawind yet,I would recomend you take a look at the Northstar by BUSA.I just can't imagine how a plane with less than 700sq.in. ever ended up weighing between 10.25-12.25 lbs.The Northstar weighs about 6.5 lbs. and has 750 sq. in. area!Of course,you'll have to build it,but it's one of the best water planes ever designed and just perfect for electric conversion.Also, that pond had better be at least 150'long for a plane with that high a wing loading.I'm sory if I sound so pessemistic about the Seawind,but it seems at least 3lbs. too heavy to be a good flier.

RE: Seawind conversion
 

The Seawind is heavy due to all the fiberglass and sheeted wing. It is a true scale model that you can see [link=http://www.seawindsna.com/]here[/link].

Although Laddy's Northstar is indeed a great design for the ages, the balsa kit should not be confused with a true scale model molded from fiberglass.

We'll see how it flies soon enough as I am now scheduled to convert one for Great Planes.

RE: Seawind conversion
 

Greg,
Do you have any idea what motor, battery, speed control, prop...that you are planning to try on the Seawind? I appreciate c-grain's input and I do agree with him on the weights but just can't get over the looks of the Seawind. Very few planes catch my eyes but this is definitely one.

Thanks
Roy
76.ta
www.hppilots.com

RE: Seawind conversion
 

My four choices for extreme power would be the following:
[ul][*] Actro 40-4[*] AXI 5320/28[*] Hacker B50L geared[*] Kontronik 600 geared
[/ul]

An outrunner is always my first choice due to the simplicity and low maintenance. Since Hobby Lobby discontinued selling the Actro line due to high price, I will have to wait to have a Seawind in my hands to see if an AXI 5330 has any chance to fit. A smaller AXI 4330 may fit and keep the weight down with only a 6s Lithium requirement. We have many 10lb scale glow conversions using a 4130. It depends on how aerobatic you need the plane to be.

Since the Seawind does have flaps, they will help slow the plane for landing.

RE: Seawind conversion
 

Hi guys,It seems that the real challenge with this plane is the prop diameter limitation.I tend to agree with Wendell.Most all of the large outrunners have low KV's and are designed to twist large props at lower rpm which will produce lots of thrust.With a 13"limit for the prop,you need to be turning well over 10,000 RPM in order to produce enough thrust for takeoff.If I were to try a conversion such as this,I'd start by using the new AXI 2826/8,a CC phoenix 60,12X8-13X6 on 3s-4s and shoot for 60A WOT for no more than 20 secs. or so.This combo will weigh around 1.5-2 lbs. less than the AXI 4130 system and that would lower the wing loading considerably!The Seawind is not an aerobatic plane,and needs to be as light as possible in order to overcome water drag to get up on step.I realize the smaller motor will be borderline on power for takeoff but is lighter and a lot less expensive to try.If it flies-great,it will be a lot more forgiving in the air and easier to land.If it won't get the plane off the water,then it will give you a real world idea of just how much more power is necessary.You can always use the motor and ESC. in another plane.Do you guys know what the empty airframe wt. is???If the Seawind is truly scale,then it probably has rather small control surfaces and I think you could save some wt. on radio gear.I remember when I was competing in scale contests back in the early 80's,the general rule of thumb for wing loadings was 29-30 oz. sq.ft. for models of 600-800 in. area.That was for land planes and the 30 oz. was absolute max!anything over that limit was considered an accident waiting to happen.I could be wrong here,but one thing I do know is "the lighter they are the better they fly"I will be very happy to find that the conversions you folks are working on do indeed fly well!! Good luck:D
Rich K.

RE: Seawind conversion
 

Guys:
Keep in mind the projected weight of the Seawind is 10.25 to 12.25 lbs. Lets assume 100 w/lb for a sea plane to get off the water comfortably. Lets do the math. That becomes 1025 to 1225 WATTS! 1.025 to 1.225 kilowatts.

An axi 413016 on lipos can run at 1.0 to 1.2 kilowatts if propped properly. If you use 8s then you get the speed for a smaller diameter prop as required by the Seawind. or maybe.....wait a minute!

A blinding flash of Aeroengineering insight:

A four bladed prop!!!!! But made up of two regular two blade eprops. Has anyone ever tried stacking two props to make a four blader? It would need to be pinned or CAed or lock washered to keep a 90 deg. spacing. But it might work real good. You would need a custom prop adaptor to accommodate the double thickness of two prop hubs. And balancing should not be a major problem.

HEY, I might have something here. How cool would that look with two prop disks. Maybe paint the prop tips different colors. Selection of pitch at the required diameter, times two props will directly effect the torque requirement and so the current draw. WOW I think this may really be promising.

Thinking outside of the box is really fun. Come on you experts, what do you think?

best regards, Ray Foley

RE: Seawind conversion
 

Why not just buy a four bladed prop? APC makes some.

RE: Seawind conversion
 

How about an axi 5320/28 on 10S.

RE: Seawind conversion
 

Greg,

Jsut wanted to follow up with you about the seawind, my buddy and i were looking at doing the same aircraft. we have one on order and were hoping to get some insight as to the conversion from gas to electric.

we just are in the final stages of converting a 72" j-3 cub and have used an axi 4120/14 with a jeti 70 opt plus esc and the ultimate bec. we aer very excited about getting on the lake.

look forward to reading more

RE: Seawind conversion
 

Hi guys,Has ANYONE out there built this plane and flown it yet,reguardless of power type-glo or E ??????????

RE: Seawind conversion
 

It looks like a number of glow versions have been completed and successfully. Look in the seapalne forum here on RCU. It sounds like it's working out good. Greg - any updates? I was just going to start a big Cub float plane, but might wait and do this instead.

RE: Seawind conversion
 

Anyone made a progress yet? Mine should show up in a day or so. I'm going through the motor choices now. I have a Hacker C50-14XL, a AXI 2826/12 and a Axi 4120/14 available at the moment. I think the Hacker is a bit of overkill. I guess I'll run some motocalc numbers and see what happens. [8D]

RE: Seawind conversion
 

gouda, have you made a decision about he engine youare going to use? my kit will be here tuesday and am really looking forward to hearing about your trials
thanks

RE: Seawind conversion
 

dirkstr;

No I have not. The plane just showed up on tuesday and I have been away on business. My first order of business will be to make sure nothing is damaged as received. As far as the motors, I did try running it all through Motocalc. That was a disaster, Motor calc could not identify a motor/battery system that would work. I suspect because of the possible high wing loading. I don't think a AXI motor will work because it seems you're limited to about a 12" prop. Typically they need large diameter, high pitch props. It seems the slimer guys are using 3 bladed props with some good success. So that may be a possibility, so a lower ratio gear drive might be the way to go. If that holds true, the big Hacker would be the best choice. I'll do some moreMotocalc work and see what I can come up with.

RE: Seawind conversion
 

Greg, any updates on your Seawind?

RE: Seawind conversion
 

HEY THANKS, LOOK FORWARD TO HEARING.

F Y I I DO KNOW THE FIRST NAME OF OUR UPS DELIVERY GUY, IN FACT HE STOPPED ME ON THE STREET THE OTHER DAY BECAUSE I WAS NOT HOME AND HE HAD STUFF FOR ME

RE: Seawind conversion
 

Well, I unpacked my Seawind this morning. Everything was fine except some minor damage to the canopy. I have already written to Tower, so hopefully there will not be any issues with getting a replacement. Dang, this is a big airplane with almost no wing. It's really a nice piece of work. GP needs to hire a packaging Engineer however. Helloooo....

Cgrain, I don't believe a 2826 would even come close to flying this plane, I just to big/heavy with to high a wing loading. A 4130 would even be marginal IMO. But I'm going to do more motocalc work and see what I can come up with. Now at least I can weight the bits and have a better idea of the empty weight.

RE: Seawind conversion
 

Damage....

RE: Seawind conversion
 

I just got my Seawind this week. I am planning on putting an AXI 4130/20 in it with a 2 Thunder Power 3S 4200Mah packs. I believe I can save weight by not putting retracts or the fixed gear in. I really am looking for more input on what power system to use, especially the battery choice. Any thoughts?

RE: Seawind conversion
 

6.47 lbs is what the basic airframe weighs without any landing gear. Add in a estimate of your radio equip and linkages etc and you can use motocalc to get a estimate of performance and motors required. I mentioned I would do that and post some results, just have not gotten to it yet, maybe by tomorrow morning.

RE: Seawind conversion
 

JUST RECEIVED MY SEAWIND, AND AM CRUSHED, ACTUALLY THE PLANE WAS CRUSHED, THE CANOPY WAS DESTROYED THE LEFT WING AND WING TIPS ARE BROKEN THE CENTER SERVO MOUNT IS MISSING, PROBABLY IN THE FUSE SOMEWHERE, AND GOING TO CONTACT TOWER NOW AND HOPEFULLY THEY HAVE PARTS.

AM STILL CURIOUS ABOUT ELECTRIC ENGINES?

RE: Seawind conversion
 

GUESS WHAT? TOWER IS OUT OF STOCK AND IS HAVING ME SEND THE ORDER BACK, AND THEN I HAVE TO WAIT UNTIL THEY GET A NEW SUPPLY, I GUESS IT COULD BE WORSE.

SEAMS THAT HTERE IS AN AWFUL LOT OF DAMAGE TO THIS AIRCRAFT SO MAYBE THEY SHOULD BE PACKAGING BETTER

RE: Seawind conversion
 

I have ordered and received three ARF aircraft and 2 RTF boats from Tower over the past 6 months, all were cheaply made and or defective. It seems that their products are manufactured in Asian countries and they just havent found the right manufacturer. I have found, by talking to my clients, that there are many good manufacturing companies in China, however, there are many bad ones also. Tower's importers only found the bad ones. It's just a darn shame, many of the hobby products become throw away items before they even get to the flying field.

The products all have design and manufacturing defects, built in fatal flaws that make the item useless. However, Tower still provides good support service and they handled all complaints in a professional manner by giving credits or sending after market replacement parts. I'm kinda getting the feeling that Tower is slipping into being just another toy company.

From now on I will not buy kits from Tower, only hobby supplies. The only way to stop the sale of defective products is to speak up. We hobbiests are just inclined to fix the item and not say anything, this, in my opinion, hurts the hobby.

Al G.

P.S. Tower's prices on Kokam LiPros is very good. Compare the price on the 3S, 2000 MAH packs (Cell Pro), you will see what I mean.

RE: Seawind conversion
 

Strange that some have very little of no damage and others are beyond hope. I wonder if somebody dropped a container or something. They must not be looking at the kits before they leave the warehouse. Mine must have been at the bottom of the pile. It shipped about 11/23. I opened it on 12/3. With only a small crack in the canopy. I sometimes wonder about the UPS/FedEx/DHL delivery people as well. I never have a issue with stuff coming to me, but stuff going to one particular area I have lots of issues with. Oh well. good thing it's so cold out anyway.

RE: Seawind conversion
 

UP HERE IN THE NORTHWEST IT IS PERFECT FLYING EATHER, IT IS ABOUT 45 DERGREES AND THIS TIME OF YEAR WE GET A LITTLE MORNING FOG TAHT BURNSOFF BY AROUND 10 AND THERE IS NO WIND AT ALL, OH WELL I WILL HAVE TO WAIT UNTIL NEXT YEAR, AS ACCORDING TO TOWER THE SEAWIND IS BACK ORDERED UNTIL LATE DECEMBER OR EARLY JANUARY AND THEY WANTED MY WHOLE KIT BACK

RE: Seawind conversion
 

That would be great weather, I agree. Our water is a bit "hard" right now.

RE: Seawind conversion
 

Has anyone gotten anywhere on this project? I couldn't find a setup of motor and battery that would work (using motocalc). That is unless I added 10" to each wing. I believe it can be done however. So lets not give up.

RE: Seawind conversion
 

I have an AXI 4130/20 and will be using two 4S 4200 mah packs. I am planning on using a 4 blade Vario prop in order to get the most out of the outrunner. I do think there are some facts about this aircraft most people are overlooking. Everyone is quick to dismiss it as an electric candidate because of the high wing loading. However, it does fly on glow power WITH retracts, which, by my calculations, would be heavier than an electric without retracts by about two pounds. A large amount of the weight savings comes from the ability to balance the aircraft using the battery packs. If you look at many of the glow build forums, everyone is having to put around 13 oz of lead in the nose to balance out the heavier glow motor and fuel tank. Thats almost 1 lb of weight we electric guys save right off the bat folks! Also, I believe the wing loading issue is being blown out of proportion. I fly jets (full scale) for a living and belive me there is a lot of lift that comes from other places than just the wing to keep them in the air. The point is, if you look at the seawind, the hull itself will be a tremedous lifting surface once airborne. In my humble opinion, only taking the wing area into consideration to calculate the wing loading on this aircraft is simply inaccurate. I am currently building the seawind right now. When I return from my flight today, I will have an entire week to devote to this awsome aircraft. I will be posting my progress and findings later on in this forum. Lets keep this going!

RE: Seawind conversion
 

Yup, I agree completely. that's why I'm not giving up. I have a Hacker, C50-14XL that I think will work well, might even be over kill, and a AXI 4120, that I think may be marginal. Being Christmas time, I don't think I be buying any other motors for a while. The gearing (6.33/1) may not work so well with a smaller dia prop though. Hummm, back to motocalc

RE: Seawind conversion
 

I ran a Motocalc estimate with the AXI and 8S lipos. I added 100 sq in to make an allowance for the fuse lifting surface (a guess, I know). It looks very possible. At least enough so to keep my interest up. I'll try the Hacker next.


MotOpinion - Untitled
800ft above Sea Level, 29.92inHg, 60°F

Motor: Model Motors AXI AC4130/20; 305rpm/V; 1.6A no-load; 0.099 Ohms.
Battery: Thunder Power TP2100; 8 series x 3 parallel cells; 2100mAh @ 3.7V; 0.022 Ohms/cell.
Speed Control: Generic Brushless ESC; 0.006 Ohms; High rate.
Drive System: APC 12x8 Electric; 12x8 3-bladed (Pconst=1.08; Tconst=1) direct drive.
Airframe: seawind; 776sq.in; 132.8oz; 24.6oz/sq.ft; Cd=0.046; Cl=0.48; Clopt=0.63; Clmax=1.11.
Stats: 70 W/lb in; 59 W/lb out; 24mph stall; 33mph opt @ 63% (101:09, 96°F); 37mph level @ 70% (86:38, 100°F); 1130ft/min @ 23.2°; -252ft/min @ -5°.

Power System Notes:

The full-throttle motor current at the best lift-to-drag ratio airspeed (19.3A) falls between the motor's maximum efficiency current (19.4A) and its current at theoretical maximum output (118.2A), thus making effective use of the motor.
The voltage (28.3V) exceeds 12V. Be sure the speed control is rated for at least the number of cells specified above.

Aerodynamic Notes:

The static pitch speed (60mph) is within the range of approximately 2.5 to 3 times the model's stall speed (24mph), which is considered ideal for good performance.
With a wing loading of 24.6oz/sq.ft, a model of this size will have flying characteristics suited to the intermediate pilot, for use in calm to moderate wind conditions.
The static thrust (91.6oz) to weight (132.8oz) ratio is 0.69:1, which will result in short take-off runs, and no difficulty taking off from grass surfaces (assuming sufficiently large wheels).
At the best lift-to-drag ratio airspeed, the excess-thrust (52.5oz) to weight (132.8oz) ratio is 0.4:1, which will give strong climbs and rapid acceleration. This model will most likely readily loop from level flight, and have sufficient in-flight thrust for many aerobatic maneuvers.

General Notes:

This analysis is based on calculations that take motor heating effects into account.

RE: Seawind conversion
 

Hey guys... just got my Seawind for Christmas. I too am interested in possibly going electric with this plane. I already have an AXI 4130/20 and an AXI 4120/14. Anybody come up with any more possible setups?

John

RE: Seawind conversion
 

To maintain a smaller prop like 13" size on a 10lb-12lb plane and provide awesome performance, you need a high Kv motor capable of turning high RPMs/v and peaks of 1500w-2000w power output.

One such motor is the [link=http://www.hobby-lobby.com/actro-32.htm]Actro 32-3[/link] at Hobby Lobby.

I recently did a similar hop-up to my 9lb Lil Toni Racer from Great Planes. I decided to swap out the entire power system with new components that could easily handle a 2000 watt power level. The new [link=http://www.fmadirect.com/new_applications/BPHDSplashPG/index.htm]BalancePro HD[/link] (formerly Skyvolt) system from FMA Direct provided the ultimate Lithium pack operation and safety needed for this high-performance aircraft. The 6s2p BalancePro HD 6400mAh pack weighs 39oz. and can deliver 2100 watt power levels without any stress, excessive heat, or loss of longevity. When using the BalancePro HD 6s charger and Discharge Protection Module (DPM), every cell of my Lithium pack is protected during charge or discharge. The DPM connection is made inside the fuselage but the final DPM-to-ESC connection using the Dean’s Ultra plug is made externally under the fuselage after the wing has been installed.

Note that a 6s1p Kokam 3200 pack will also work here but the lighter weight also has shorter flight times and less top end power. You'll need to adjust the prop for a 60amp peak current level.

The existing motor was changed to a an Actro 32-3 outrunner. Using the same 14x7 e-prop as before, the current now measured 104amps at 2200 watts. That was 244w/lb.! The new Phoenix HV 85 ESC provided great throttle control and was an over-kill for the 2200 watt application since it is capable of handling up to 4000 watts (or 5h.p.). Note that a [link=http://www.hobby-lobby.com/jetiblue.htm]Jeti 90-amp[/link] ESC will also work well. For the Seawind, the prop can be changed to a smaller 13x8 size and maintain a full throttle setting at around 1500 watts. A nice 12" 3-blade like the [link=http://www.hobby-lobby.com/grprop.htm]Graupner Super Props[/link] would look great on this model and provide similar performance to the 13" prop.

Good luck!

RE: Seawind conversion
 

Anyone else get anywhere with this conversion? I've been stuck on a Cub build that should be done in a few weeks. The Cub uses a motor I have, while the Seawind is going to take a new motor purchase. My funds are limited after Christmas for a few weeks. I am going to look at the new E-Flite 60 sized motor however, seems like a good alternative to a AXI and they include the prop adapter mount etc. Anyone used one yet?

RE: Seawind conversion
 

I heard from Hobbico recently so I should be getting my Seawind in a week or so. I'll likely still go with the Actro 32-3 for high RPM power using a smaller prop.

RE: Seawind conversion
 

I have a hacker Brushless B50-13XL /1214 rpm, would this be a good choice ?