Greg Covey

The Corsair madness continues this year! Here are some photos from last weekends local event. Notice the Robart strut modification to the stock landing gear on the takeoff photo.

This year, I'm using a 6s5p configuration of Kokam 1500mAh cells. The H9 Corsair doesn't mind the extra weight and the flight times are about 15 minutes.

algutkin

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HI:

This is an update to the Hangar 9 Corsair, gas to electiric conversion.

The Hangar 9 ARF kit does not have a full backing plate behind the firewall. Which means that if you drill new holes and install blind nuts, there is a chance that the blind nuts can cause the firewall to crack and the electric motor will pull loose. The firewall is only 1/8 inch in spots.

I uploaded a picture which shows my 1/4 inch backing plate that helps to reinforce the firewall/engine mount. This is not a perfect fix, however, it will probably suffice. In retrospect, I might have used birch plywood instead of the solid poplar that I did use. The first piece did crack when the blind nuts were tightened.

Hope I helped.

Al G.

CorsairJock

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I just installed an all new 3/16" firewall on mine, attached to the modified, rounded forward fuselage (rounded as the full scales are, to allow air to exit engine comaptment past cowl flaps). Also, I installed a Top Flite cowl, rather than standard H-9 cowl.

Greg: your pictures aren't showing up.

Here are a few more of mine, taken with late evening sun shining brightly at Howell, MI club site.

algutkin

My Feedback: (1)

Great pictures Jack. How did you end up powering your craft?

Mine will be finished this weekend, waiting for the prop adaptor and prop. Unfortunately, mine is completely H9 stock nitro, converted to electric.. I have had two of these planes with 100FA Saitos for some time, now it's all electric for me, just received the new cowls from Horizon and will be selling those 100FA Saitos on Ebay this week.

More pictures Jack, if you please.

Al

CorsairJock

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All details are posted in a previous post (#248), but here is general info:
Motor: the tried, trusted, and proven AXI 4130/16
Prop: varies, but allways 14". Flies well with only a 14 x 6, and draws less than 20 amps with that size. With 14 x 8, it rivals the fuel powered ones in speed. Will even swing 3 blade Master Airscrew 14 x 7, while drawing about 31 amps (all currents are static). The 3 blade looks GREAT, but is not the most efficient.
ESC: JETI 40P, which is needed for the 6 cell Li-Po packs
Battery: now using 4400 mAH rated, 6S Li-Poly. Cost about $160 for the 2, 3S packs (wired in series). I am gettting over 12 minutes of flight time per charge. I could go longer, but don't want to push it. Actually, I usually fly twice per charge, getting in 2, 6 minute flights.
AUW: it's been awhile since I weighed it, and so I forgot exact measuremt, but it is around 8 lbs, 6 oz, which is less than my fuel powered Hanger 9 Corsair.

Here's a late evening pic taken at the 2005 Mid Am Electric Fly-in hosted by Keith Shaw and Ken Myers. This marked the 1st time that they presented an award for an ARF, mainly due to the vast amount of kit bashing that I performed on it. It was awarded "Best Scale", and I truely appeciated getting such an award from these 2 electric gurus.

algutkin

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Jack:

Thanks for taking the time to respond, your pictures are a work of art. If they were mine, I would frame them and put them on the wall in my office. Actually, I would be tempted to put them up even if they weren't mine, however, if a client asked questions, my answers would indicate that I was not that knowledgeable and there is no way I would even think about taking credit for such good work. Jack, I say again, your craft along with those pictures are works of art, excellent! What's next?

I have a B25 kit sitting in the garage, how about you making one first, then after you get the kinks out I can copy it? LOL

Al

CorsairJock

My Feedback: (90)

Thank YOU, for the compliments. I DO use them a 'background' on my computer. Most of the pictures are taken by my wife. The exception is the 3 in flight ones taken at Howell, MI, which were taken by a a local club member while I was visiting. His pictures were outstanding, I had to downsize and crop them in order to download them here. The originals are even sharper then the ones posted.

Next big electric project? I don't know yet and it won't happen before this coming summer. So many choises, so little time. I have 2 projects which I started a long time ago, with original intention of fuel power, but am now thinking electric:
Top Flite 'red box' Zero
Jemco/ Master Scale SBD Dauntless.

I would LOVE to complete either of both as electric powered. The Dauntless has the fuselage nearly completed, including provisions for motor mount and fuel tank. It would require a little re-working. The Zero has wing construction only begun, which means NOTHING would have to be re-worked yet. I'll have to decide which one to move forward on by late summer, as I intend to do one or the other NEXT winter.

In the mean time, here is one taken by a Terre Haute, IN club member at their 2005 Memorial Day Warbird Fly-In. BTW, I was 'dog-fighting' with a .46 powered Seagull Zero at this event, and was actually turning inside of it/ GAINING on him in sustained turning manuevers (mine must have lighter wing loading) and keeping up with it in straight and level (retracts on mine helped).

algutkin

My Feedback: (1)

Jack:

Think B25, think B25 ARF kit, think you can finish it before the summer? It was written up in Model Airplane News approx. 5 months ago. Real kits take too long, life if short, think B25 ARF. Wouldn't you really like a twin? LOL

In all seriousness, what type of camera does your wife use. What type does the club member use? I have some of the best cameras and pictures don't come out like yours. I take pictures just like I fly, crappy. Is your wife a professional photographer?

Looking forward to seeing and reading more.

Al

modeldesigns

Hi Everyone,

Thanks to pioneering work by John Ranson in the UK we can now get closer to having an authentic sound in our models.

The link takes you to a video of my Hanger 9 Corsair fitted with the German Benedini sound hardware similar to that trialed by John in his Heinkel 111:


http://media.putfile.com/Corsair-wit...rdon-Whitehead


...make sure you turn your pc volume up and enjoy!


The Corsair's flying weight has increased from 9lb to 10-1/4lb. Power is still my usual Axi 4130/16 on 6Ah 6S TP ProLite cells and a 16"x10" pattern prop. The total flight in the video used 2.5Ah from the flight cells and 0.4Ah from the amplifier battery.

The sound sytem can remain turned off if the flying site dictates...so we have the best of both worlds.

Anyone for smoke on start-up?!


Cheers,

Pete (Wiltshire, UK).

algutkin

My Feedback: (1)

Hey Pete, the sound is really great, smoke would be good also.

However, it's too late to change the existing units as the electric conversions emulate the removal of the 9 cylinder radial and the installation of a smoke free turbine. LOL

Al

modeldesigns

Hi Al,

Our ground crews were faced with the same problems following service using a smoke free turbine.

Just look away as you take a hacksaw to the front end...the new noisy turbine installation will then follow with enthusiasm!

Pete.

algutkin

My Feedback: (1)

Pete:

Electric conversions actually sound like turbines, that's one reason I love them. Why make them sound like turbines that were retrofitted with radials? LOL

I typed a whole scnereo of how and why the radials start, smoke, drip oil and cause their pilots to have nerve damage and become hard of hearing. I had to erase it all, it got way off subject. However, I agree, there is nothing sweeter than hearing the sound of a radial powered plane performing a low pass down the runway. I just wish I could hear as well as I used to.

Al

CorsairJock

My Feedback: (90)

An increase in weight by 1 1/4 lbs sounds a little too significant to me, and I would be willing to sacrifice some volume for less weight: what about using one speaking pointing down and forward, and using a slightly smaller one?

Also, no mention of battery voltage used to drive this: what is series cell count (Li-Po?)?

I have a RAM unit that I intended to install in mine: much lighter (about 4 oz complete with 3 cell, 500 mAH Li-Po) BUT it sounds AWFUL, and lacks the starting up/ idling sounds. SO, I would consider one of your units, if I could get more info (price)?
In other words: where can I get one and how much?

algutkin

My Feedback: (1)

Opinion needed,

My conversion is now finished except for the batteries and CG balancing. Removed a Saito 100 and installed an Axi 4130/16 with Greg's battery setup, 6S4P batteries. However I have been unable to find a 15X8 Graupner three blade. Hobby Lobby back ordered them which made me very upset due to lack of their communication. I had to settle for a 13X8 three blade obtained locally, but I'm not sure the smaller prop will put out enought power. This setup only draws 27 amps at full throttle.

I tried Motocalc and Electricalc but the results left me with too many questions. It appears that actually flying the plane would be the answer, however, I'm not good enough and don't want to screw up this plane. I'd really like to show up at the field with a plane that is set up right from the start.

Any thoughts on the matter? Will the 13X8 three blade enable the plane to fly adequately.

Al

CorsairJock

My Feedback: (90)

I have been using 2 blade props ranging from 14 x 6 to 14 x 8 on mine (same motor/ battery setup), and it flies GREAT!. In fact, I don't understand why so many are choosing the 15" sizes for these Corsairs. Maybe the 10 lb one with sound needs one, but these usually end up at 9 lbs or less AUW (with Li-Po 6S pack). My thoughts are that the 3 blade graupner 13 x 8 will work, but may not provide the performance you may want. Have you considered tha Master Airscrew 3 blade props? They make a (3 blade) 14 x 7, which I am SURE would work well. In addition, it is black (rather than gray)/ more realistic looking.

modeldesigns

Hi CorsairJock,

If you are willing to sacrfice an amount of volume then going the single 4" speaker route should reduce the additional sound payload by around 7ozs. This would represent the savings due to omitting the second speaker and its sound box structure.

If you look at the pic, for your Corsair you could rotate the speaker sound box and integral motor mount through 90 degrees and leave off the stucture for the second speaker sound box. This would leave the single reamaining speaker pointing downwards and forwards.

Much work has already been done on different speakers but the 4" Visaton speaker recommended by Benedini, the sound hardware supplier, still provides the best overall balance between size/weight/sound and cost...but there could well be an even better alternative not discovered yet!

I am using a 3S 1600mAh LiPo battery to power the amplifier, which weighs 4ozs. A 1200mAh pack should provide enough power for a single, 10 min flight and weigh a little less. We are hoping to trial a BEC style power source for the amplifer soon, which will be lighter still.

Here is the link to a second video of the Corsair with sound. The horrible scaping sound you can here when taxiing back is the hard plastic tailwheel. I had swapped out the supplied softer foam ones as they tend to flatten off, but i need to change them back now!

http://media.putfile.com/H9-Corsair-with-sound

The German Benedini high power amplifier and programmed sound module cost 150.00 UK pounds. The 4" Visaton speakers are 7.00 UK pounds each. Here is the link to the Watt Flyer web site detailing developments in getting sound into models:

http://www.wattflyer.com/forums/showthread.php?t=573

Hope this all helps,

Pete.

algutkin

My Feedback: (1)

Corsair Jack:

Thanks for the info, 3 blade Master Airscrew would be just fine, except, they are not available locally. Here in So California the hobby stores sell more RC cars and trucks than planes so, big props are impossible to find. I guess I will have to eat some crow and buy a Master Airscrew from Tower Hobbies. The last order from them took 10 days from Reno to CA, by snail mail and I let them know about it.

Al

CorsairJock

My Feedback: (90)

Great News: Master Airscrew has just announced that they are now making a 3 blade 15 x 7. Should be Perfect for those wanting to draw about 40 ~ 45 amps from their AXI 4130/16.

I haven't been able to find one yet (I checked Tower), but they should be available within the next few months

Rob Schaffer

FlyinTango, any updates on your flights with the 16x10 3 blade? Sounds like your amps may be alright once you throttle back in the air, but 47 amps on the 4130/16 is a little higher than they seem to like. Just wondering how you made out.

Rob

algutkin

My Feedback: (1)

The Graupner 15X8 three blade is now available again. Why wait months for a Master Airscrew? I haven't had a chance to fly the Corsair with the Graupner yet, but, it sure feels lots better than the 14X7 three blade and my 70 amp Jeti doesn't even get warm.

Al

CorsairJock

My Feedback: (90)

Anyone ever bother to check efficieny with these (AXI 4130/16) motors? According to Electric Motor Calculator, maximum efficiency is at about 25 amps with 6S Li-Po. For practical purposes, setting up for for between 125 ~ 150% of that (static) means it will be most effiecient when airborne. That means: most power for the watts consumed. Pushing beyond 150% reduces effiency, and starts to tax the motor (and batteries) more. 150% of 25 amps is 37.5 amps, which is PLENTY of power for the Hanger 9 Corsair. I know, because mine is flying with only about 27 amps static draw, and it performs all scale manuvers and respectable hi-speed passes.

Using an over size prop and then not using full throttle does NOT improve efficiency.

So why then, do so many want to over prop their AXI motors? If size (large diameter) and 3 blade props is what you want, the Master Airscrews have more narrow blades than Graupners, thus it only goes to reason that they will 'pull' less amps. If you are pulling 40 amps or more, you are over loading your motor IMO.
Just my 2 cents

BTW (again): how good does mine fly? Good enough to win "Best Scale" at the 2005 Mid America Electric Fly-in, hosted by Keith Shaw and Ken Myers

algutkin

My Feedback: (1)

Hey Jack:

I have read lots of your posts and you seem to know what the heck you are doing, congrads. on your awards. However, some of those threads that contain the results of your experience get burried deep in the data base of RC Universe so you have to keep posting the results of your experience. Ya know, like use a word processor and copy and paste the same info. in every new thread.

I, for one, hate to think that I have to invent the wheel with every project. If I could find a fast way to get to the end result it sure would make things easier. My starting info regarding the Corsair came from Greg Covey's conversion. However, it's not easy for some of us to purchase the exact prop for the project, we loose our patience waiting for the UPS driver, Fed Ex driver or the snail mail to deliver our research material, wo we tend to try what we have. I tried a Master Airscrew 14X7 three blade, stalled the plane from base to final and had to build a new craft. The new craft has the 15X8 three blade prop. and seems to make enough power on the ground to enable a hover. If I only knew how to do it.

Al

CorsairJock

My Feedback: (90)

algutkin, you are correct and I apologize: I post things in many places, and cannot keep track of what I said and where, and what I haven't said. And I don't mean to sound like I am bragging about the awards: I just want emphasize that what I have done to this Corsair as far as power system has the approval of everyone who sees it fly, including some very well known and highly regarded 'electric gurus'.

Also, my comments are not aimed at any one individual, as it seems that the vast majority of H-9 Corsair electric conversions are 'over-propping' their AXI 4130/16, IMO.

So, allow me to back track a little, and add some things that I have probably stated nowehere else.

My decision to use the AXI 4130/16 was based solely on my experimenting with the "Electric Motor Calculator", mentioned in my previous post. This is an online program, FREE for anyone to use, and it provided all of the data I needed to make the decision. When I decided on the AXI, I was completely un-aware at the time that so many others were building H-9 warbird projects using the same motor and Li-Po battery confuration (6S, 3200 ~ 6000 mAH). Here is a link to that calculator:
http://brantuas.com/ezcalc/dma1.asp

NOTE that not all electric motors are listed, not even all AXIs. Also note: the propellors are caluculated and limited, and will provide only semi-accurate results. I have found for example, that the Master Airscrew 3 blade props draw about 10% less current than the calculator indicates. Also note: battery choices are limited, as far as manfacturur and capacity. The Kokum 3200 Li-Po is listed however, and should be very close to any other large capacity Li-Po cells in terms of current draw, thrust, and RPM readings. However, I have no reason to believe that motor efficiency numbers are in-accurate. I was able to determine the general range of prop sizes that would best suit my needs tho, with further testing using actual amp and volt meters helping to make final determinations (and flight testing).

As stated in a previous post (here, in this thread), I have never used anything larger than a 14" prop. My Corsair most certainly will not hover, then gain, I have never seen a full scale Corsair hover, and I don't think the H-9 warbirds are built sturdy enough for extreme acrobatics anyway. They are lightly built, fly great, but some have encountered structural failures with them (as in: wings coming off). So I don't push mine beyond what the full scales did and what I have seen them do at airshows.
It WILL take of rather abruptly, after about a 100 ft roll (from grass runway), and has a respectable climbout (not vertical), and is capable of those giant, scale looking loops, as well has high speed and low speed passes, barrel rolls, aileron rolls, etc.

I now have a pair of AXI 4130/20s, and have concluded that these motors are the ones to have if you like bigger props. I experimented yesteday with a Master Airscrew 3 blade 16 x 8, and current draw was only about 30.5 amps (6S Li-Po). BUT, it sure had a lot of thrust: this setup just might pull an H-9 warbird straight up. I will be using this motor/ prop setup in my Jemco Dauntless, to be completed by NEXT summer (you heard it first here).

Lastly: I don't understand the correlation between using a Master Airscrew 3 blade 14 x 7 AND stalling a plane on base to final (and crashing?): could you elaborate?

algutkin

My Feedback: (1)

Jack:

MY comment to you were meant as compliments. I read in previous pages about your setup, you performance etc. However, I just didn't want to re-read that many pages to find the info again. That's why I suggested that with every post you list the stats.

Motor /controller/battery setup
AUW
Prop Size

RE: The crash. I was flying the Corsair like a trainer and stalled it from base to final. It was pilot error. I was flying at half throttle and made a 45 degree turn to final when it went into a stall spin. At half throttle, I just didn't have the airspeed to make that steep turn. It seemed that it took almost 3/4 throttle to full power just to keep the plane at a reasonable pattern speed. I leared, now I'll talk to myself, "keep the speed up, it's not a trainer" However, the 15 inch prop. sures feels lots better on the ground, can't wait to try it, still tied up with business, perhaps at the end of the month.

Please keep on posting, you are not bragging in a negative way, you are just proud of your accomplishments, who isn't? You earned it, and you inspire the novices like me.

Al

tahustvedt

Did you use the stock numbers from Model Motors in EMC? The internal resistance for one is way off the actual value. The specified internal resistance for the 4130/20 is 99 mohm but in reality I think it's closer to 40-50. If I want the performance of the 4130/20 to reflect real life performance in Motocalc I have to set the kv to 285 and the resistance to 45 mohm. I then get realistic figures at load RPMs with 8S.

With a Master Airscrew 16x10 3-blade prop and 8S with a 4130/20 I get the following numbers. The thrust, rpm, amp and watts are close to what my real life measurements show:
AirSpd (m/s) = 0,0
Batt Amps = 47,8
Motor Volts = 26,9
Input (W) = 1284,4
Loss (W) = 203,8
MGbOut (W) = 1080,6
MotGb Ef(%) = 84,1
Shaft Ef(%) = 76,4
Prop RPM = 6670
Thrust (g) = 4494
PSpd (m/s) = 28,2
Prop Ef(%) = 0,0
Total Ef(%) = 0,0
Time (m:s) = 5:01


I prefer lower kv motors because they enable me to spin large scale props and even multi-bladed props. I have rewound an AXI 4130 to 24 turns and this enables me to spin a 20x13 with ease and right now I'm running a DIY 18x12 four-blade propeller on my aerobatic plane with this motor on 8S. Efficiency is very good. With a 4000 mAh battery and a 20x13 prop I have flown for over 19 minutes.

Here's a picture of the plane with the four-bladed prop: http://enrarot.net/images/velox44.jpg

I plan to rewind another 4130 to 28 turns or thereabout to spin a 20x15 four-bladed prop for a Spitfire (maybe five if I'm feeling crazy).