H9 15cc Carbon Cub

[AKNick]

Yeah, I'm not that crazy about the angled plugs either, like going with the tried and true, it's good to hear the casting is improved, but to be honest if the older version like yours were still available, I'd probably get one of those. "Improvements" always kinda worry me a little. The angled plugs do make it slightly narrower, but the plug ends are now ending up at a lower spot in the cowl, so the inward curve of the cowl makes the width in that spot a little less, and it seems like the engine to cowl clearance isn't much more than it was before as a result.

I think they did away with the external vacuum line for the carb pump too, at least I don't see a line on the new version, so maybe they are using internal carb suction for the carb pump like many other Walbro carbs do.

Your 21T setup just looked and sounded amazing in the video, even if the vibration may not be much less, the twin engine just looks so much more "realistic" and scale like than any other engine, and definitely than an electric motor. I'll try to post some pics as soon as I get that far.

I had some standard size analog servos, Hitec HS-311, I am using those for ail/flaps, just to avoid having to spend $25-30 on each servo. Do you think there will be any problem with those servos since everyone and the manual seem to suggest high torque or digital servos? They seem like they have enough torque, at least if I run them on 6V. I might use something a little more heavy duty on the elevator and rudder since those surfaces might see a little more load due to their larger areas/deflection.

Thanks again!

Those HS-311 are not suited for gas engine vibrations. I looked them up, they are analog, nylon bushing, 3-pole ferrite, with 50oz/in at best torque with resin gears... they will eat themselves.

Get some standard metal gear servos closer to 80oz/in.

As far as the pulse port, I’m not sure what changes they made.

 

[Bradlee]

Those HS-311 are not suited for gas engine vibrations. I looked them up, they are analog, nylon bushing, 3-pole ferrite, with 50oz/in at best torque with resin gears... they will eat themselves.

Get some standard metal gear servos closer to 80oz/in.

As far as the pulse port, I’m not sure what changes they made.

You are absolutely right. Not worth the risk. I hate spending money on servos, lol, because you rarely need just 1 or 2, like engines, but it's a must I guess. Don't wanna risk losing all the stuff due to 1 faulty servo.

I might get Power HD 20 or some HK 20kg digital servos. They're fairly cheap but have the necessary specs, incl. metal gears. Very good advice!

 

[AKNick]

You are absolutely right. Not worth the risk. I hate spending money on servos, lol, because you rarely need just 1 or 2, like engines, but it's a must I guess. Don't wanna risk losing all the stuff due to 1 faulty servo.

I might get Power HD 20 or some HK 20kg digital servos. They're fairly cheap but have the necessary specs, incl. metal gears. Very good advice!

I have the servos from my Carbon Cub if your interested. The guy that purchased my plane wanted to go another route. Not sure what radio system you are using or power source.

 

[dhal22]

I'm the opposite, I love expensive servos. The Hitec 9380's are amazingly fast and strong. Going to buy a couple of the new Futaba A700s just to admire.

I know, off topic.

 

[Bradlee]

I have the servos from my Carbon Cub if your interested. The guy that purchased my plane wanted to go another route. Not sure what radio system you are using or power source.

Oh cool, that's great. I have lots of options as far as radio goes, probably 2.4GHz with something with good transmission power, either FrSky or Spektrum DSMX. Futaba is pretty good too as far as spread spectrum goes, but they don't have a lot of Tx power, a little less than 10mW one time I measured, the other 2 brands are close to 100mW. Either way, all 3 probably have the best interference resistance to possible RF noise from the spark ignition, as opposed to anything on 72MHz. 7 or 8 channels so flaps and ails can all be programmed, I don't trust servo reversers a lot.

I have regular 4.8V and 6V NiMH battery packs for power, but I will probably go with A123/LiFe or 2S LiPo packs, so 6.6V or 7.4V most likely, with lots of capacity, 3000 to 4000 mAh, and a separate 7.4V/2400 mAh batt for ignition with an opto kill switch, but ignition won't affect the servos though. Depending on what the servos might be able to handle, I might wait to pick the RC receiver power system based on that. 6V is likely a happy medium for most servos.

What type of servos do you have again? I assume you have all 6 still? Let me know what you are asking for them and everything, and I'd love to get those from you. I assume they are digital MG servos. Thanks for letting me know you still had yours.

 

[Bradlee]

I'm the opposite, I love expensive servos. The Hitec 9380's are amazingly fast and strong. Going to buy a couple of the new Futaba A700s just to admire.

I know, off topic.

No, actually I'd love to hear from everyone and what they have in mind, all inputs welcome. There's not really anything off topic as long as it goes toward the build procedure, and the type of servos you pick does absolutely have to do with that, so thanks for your input! I will check out the specs of those servos, but they sound too expensive for me though, lol, they sound like top of the line. I think I have a couple of those really high torque / fast Hitec servos, I used those to build a robotic arm with 360-degree rotation, with external gears instead of servo arms. They are expensive, but very good quality.

 

[Bradlee]

I'm the opposite, I love expensive servos. The Hitec 9380's are amazingly fast and strong. Going to buy a couple of the new Futaba A700s just to admire.

I know, off topic.

Those are def. worth admiring, especially the A700! Probably a little overkill for this model, they are in the 60 to 70 kg x cm torque range, so more suited for 40% or above models, but reading the specs, they are really jaw dropping!! Brushless, titanium/stainless gears, and super fast. Really amazing just to read the specs.

 

[AKNick]

I have regular 4.8V and 6V NiMH battery packs for power, but I will probably go with A123/LiFe or 2S LiPo packs, so 6.6V or 7.4V most likely, with lots of capacity, 3000 to 4000 mAh, and a separate 7.4V/2400 mAh batt for ignition with an opto kill switch, but ignition won't affect the servos though. Depending on what the servos might be able to handle, I might wait to pick the RC receiver power system based on that. 6V is likely a happy medium for most servos.

What type of servos do you have again? I assume you have all 6 still? Let me know what you are asking for them and everything, and I'd love to get those from you. I assume they are digital MG servos. Thanks for letting me know you still had yours.

Here's what I used/still have. I ran them off a A123 2500, TechAero IBEC, off a Futaba receiver.
Savox (x6) SC-0254MG for all surfaces https://www.savoxusa.com/products/savsc0254mg-std-digital-servo-14-100
Savox SV-0220MG throttle https://www.savoxusa.com/collection...ts/savsv0220mg-high-voltage-std-digital-servo
I even have a spare A123, I could part with.
The plane did settle into the trees at one point, softly (deadstick), and flew again afterwards. The only repair I made was a wing strut, plane never touched the ground.
Everything (7servos, A123) new is about $250, I would be somewhere near half that... If you're interested let me know and we can make a deal.

 

[Bradlee]

Here's what I used/still have. I ran them off a A123 2500, TechAero IBEC, off a Futaba receiver.
Savox (x6) SC-0254MG for all surfaces https://www.savoxusa.com/products/savsc0254mg-std-digital-servo-14-100
Savox SV-0220MG throttle https://www.savoxusa.com/collection...ts/savsv0220mg-high-voltage-std-digital-servo
I even have a spare A123, I could part with.
The plane did settle into the trees at one point, softly (deadstick), and flew again afterwards. The only repair I made was a wing strut, plane never touched the ground.
Everything (7servos, A123) new is about $250, I would be somewhere near half that... If you're interested let me know and we can make a deal.

Hi Nick,
Sorry I was out of touch for a while, was really busy so I didn't get a lot of time for this lately.

Does your servo/A123 package include the TechAero ibec as well? Why did you need a BEC anyway if it was running off of a receiver battery pack (as opposed to a higher voltage 5S or 6S LiPo pack for the ESC on an electric motor setup)? I assume so your receiver wouldn't be seeing more than 4.8 or 5V? Let me know if the ibec is included too if it is needed.

You said somewhere near half, so would 120 be ok shipped to Oklahoma? I don't know where you are located as for shipping, but from the mountains in your video, I'm guessing somewhere around CO or NM or somewhere out west, so probably not too far away.

Thanks

 

[AKNick]

Hi Nick,
Sorry I was out of touch for a while, was really busy so I didn't get a lot of time for this lately.

Does your servo/A123 package include the TechAero ibec as well? Why did you need a BEC anyway if it was running off of a receiver battery pack (as opposed to a higher voltage 5S or 6S LiPo pack for the ESC on an electric motor setup)? I assume so your receiver wouldn't be seeing more than 4.8 or 5V? Let me know if the ibec is included too if it is needed.

You said somewhere near half, so would 120 be ok shipped to Oklahoma? I don't know where you are located as for shipping, but from the mountains in your video, I'm guessing somewhere around CO or NM or somewhere out west, so probably not too far away.

Thanks

The Tech Aero IBEC is to illuminate the need for the extra ignition battery.
http://www.tech-aero.net/ultra-ibec

I'm in Alaska. One of those mountains is 4,000ft AGL!

I'll send yo a PM about the gear.