out of curiosity, how many hours on average do these brodak ARF's take for assembly/fixing?

Quote from: T.J. Vieira on March 13, 2019, 07:05:02 AM
out of curiosity, how many hours on average do these brodak ARF's take for assembly/fixing?

It's hard to say.  I am guessing I spent 5 to 10 hours putting mine together.  But I added a G10 motor mount and I replaced the bellcrank with a Tom Morris setup. (actually I installed a complete Tom Morris control system).  I also had to build a battery mount inside the battery box.  Every thing fit and it all went easy.   

I have my eye on a vector at the moment, a "just because it looks cool" kinda thing lol.  I have a Gypsy in pretty much ready to start applying silkspan, and a racer ready for assembly.  with flying season here, I'm hoping my table will only be for repairs rather than building

Haven't flown this bird in years (March 2019).  Flew it today.  Pulls like a bear as a big airplane should.  Actually made a 40 point landing.  Anyway she doesn't turn as good as I would like.  So I will tape the hinge line gaps and check the CG.  Also will go back through this thread and look at the good advice given by many.  In particular setting the flaps to elevator droop.  Looks like this is going to be be a fun aircraft.   

Hi John, thank you very much for posting information about SV-11 ARF electric - there not so many information about this kit. I have just received a parcel with Sv-11 Electric and plan to use in the future as a first full-sized plane, currently I fly smaller ones and try to make a full stunt pattern. As I understood you used Cobra motor instead of the one recommended by Brodak - how did you mount it? Do you have a photo of how the motor is mounted? Did you make some custom mount for that?

Quote from: Alex Grudev on December 21, 2021, 06:17:26 AM
Hi John, thank you very much for posting information about SV-11 ARF electric - there not so many information about this kit. I have just received a parcel with Sv-11 Electric and plan to use in the future as a first full-sized plane, currently I fly smaller ones and try to make a full stunt pattern. As I understood you used Cobra motor instead of the one recommended by Brodak - how did you mount it? Do you have a photo of how the motor is mounted? Did you make some custom mount for that?

The Cobra 3520 KV 980 motor that I used is pretty much a direct replacement for the Brodak motor. Didn't take any modifications to mount it.  I did add a Bob Hunt fiberglass mount to the back side of the existing motor mount.  Not sure it was worth the effort.  The existing mount probably is OK all by it's self.  The Cobra 3520 KV 980 is a 4 cell motor.  If you plan to use a 5 or 6 cell battery you will need to adjust the KV of the motor accordingly.

Quote from: John Rist on December 21, 2021, 10:37:04 AM
The Cobra 3520 KV 980 motor that I used is pretty much a direct replacement for the Brodak motor. Didn't take any modifications to mount it.  I did add a Bob Hunt fiberglass mount to the back side of the existing motor mount.  Not sure it was worth the effort.  The existing mount probably is OK all by it's self.  The Cobra 3520 KV 980 is a 4 cell motor.  If you plan to use a 5 or 6 cell battery you will need to adjust the KV of the motor accordingly.

I am not 100% but I think the 3520/10 will take a 5s but not a 6s.

Ken

Quote from: Ken Culbertson on December 21, 2021, 03:42:08 PM
I am not 100% but I think the 3520/10 will take a 5s but not a 6s.

Ken

True.  The cobra 3529/10 has 5s listed in the prop chart.  Ken thanks for the update.

Quote from: John Rist on December 21, 2021, 10:37:04 AM
The Cobra 3520 KV 980 motor that I used is pretty much a direct replacement for the Brodak motor. Didn't take any modifications to mount it.  I did add a Bob Hunt fiberglass mount to the back side of the existing motor mount.  Not sure it was worth the effort.  The existing mount probably is OK all by it's self.  The Cobra 3520 KV 980 is a 4 cell motor.  If you plan to use a 5 or 6 cell battery you will need to adjust the KV of the motor accordingly.

Thanks for a quick reply. And which propeller adapter do you use? As I see the Cobra engine comes with a bolt-on prop adapter and you can't use it when mounting on the existent mount - you need some collet prop adapter  to fix it on a flat engine shaft - am I right?  I am looking at BadAss 3515 motor and it also has only bolt-on adapters whilst the Brodak's recommended engine has a collet adapter.

Regarding the 4s or 5-6s: I see 2 options for myself - the first is BadAss 3515 940kv, 4S battery and 2-blade prop or the second is BadAss 3515 710kv, 6S battery and 3-blade propeller. My concern is a weight of the batteries - for 4s it will be approx. 270-300grams and for 6S it will be more than 500 grams - I am afraid that a heavier battery can move the CG forward. The Brodak recommends 4S for this model and I see from some SV11 reviews that people tend to use 4S as well. Any thoughts on this?

Quote from: Alex Grudev on December 22, 2021, 05:42:04 AM
Thanks for a quick reply. And which propeller adapter do you use? As I see the Cobra engine comes with a bolt-on prop adapter and you can't use it when mounting on the existent mount - you need some collet prop adapter  to fix it on a flat engine shaft - am I right?  I am looking at BadAss 3515 motor and it also has only bolt-on adapters whilst the Brodak's recommended engine has a collet adapter.

Regarding the 4s or 5-6s: I see 2 options for myself - the first is BadAss 3515 940kv, 4S battery and 2-blade prop or the second is BadAss 3515 710kv, 6S battery and 3-blade propeller. My concern is a weight of the batteries - for 4s it will be approx. 270-300grams and for 6S it will be more than 500 grams - I am afraid that a heavier battery can move the CG forward. The Brodak recommends 4S for this model and I see from some SV11 reviews that people tend to use 4S as well. Any thoughts on this?

The interesting thing about batteries and weight is that the energy density drives the weight. A 6s battery suitable for the flight will weigh pretty much the same as a 4s battery. I use a 5s 3000 MAH 5s in mine and it weighs 300 grams. This battery is likely the same battery that is sold by TP as a 5s 2800 MAH. I'm running a BadAss 3520 650Kv. 5:40 flight time. The E-Flite spinner I am using includes an integral collet adapter.

Battery:

https://www.rcjuice.com/lipo-batteries/5s-18-5v/hobbystar-3000mah-18-5v-5s-30c-lipo-battery.html

the 6s is 370 grams and I wouldn't hesitate to use this. My airplane came out a little bit towards the aft CG zone and I added a bit of nose weight, about an ounce.

https://www.rcjuice.com/lipo-batteries/6s-22-2v/hobbystar-3000mah-22-2v-6s-30c-lipo-battery.html


Spinner:

https://www.towerhobbies.com/product/2.00-aluminum-spinner-with-4mm-and-5mm-collets/EFLSP200.html

The round Lithium ion batteries are more power efficient per volume than the poly bag cells. A six cell 2600 pack would weigh in around 320 grams but the package won't fit through the cutout.

I bought the spinner adaptor from Tom Morris.  All of Tom's stuff is being sold by Okieair.  Okieair lists a 2" two bladed reverse pitch spinner.  However it does not say that it has a 5mm collet built in.  The one from Tom did have the 5mm adaptor built in.  A call to Okieair would be in order to make sure.
https://okieair.com/shop/ols/products/2-reverse-pitch-spinner

The prop I am using is an APC 12 x 6 EP.   There is a lot of discussion on the electric board about which is better, tractor or pusher prop.  I am mostly a sport flyer so I am not up on which is best.  All my electric airplanes have pusher props.  They seem to give me good line tension for most of my flying.  But like I say, what do I know.

Every thing I have flies on 4S.  That is one of the reasons I went with 4S on my SV-11.  It seems to work so I am happy. Another point I would like to make is that right now I am trying to learn the beginners pattern so I only fly for 4 minutes. The put back in the 4C 2800 battery was 1537 mah for a 4 minute flight or about 54% usage.  So when I want to move up from the beginners pattern I should be able to do 5.5 minutes without going to a bigger batter pack.

Quote from: John Rist on December 22, 2021, 09:49:05 AM
I bought the spinner adaptor from Tom Morris.  All of Tom's stuff is being sold by Okieair.  Okieair lists a 2" two bladed reverse pitch spinner.  However it does not say that it has a 5mm collet built in.  The one from Tom did have the 5mm adaptor built in.  A call to Okieair would be in order to make sure.
https://okieair.com/shop/ols/products/2-reverse-pitch-spinner

The prop I am using is an APC 12 x 6 EP.   There is a lot of discussion on the electric board about which is better, tractor or pusher prop.  I am mostly a sport flyer so I am not up on which is best.  All my electric airplanes have pusher props.  They seem to give me good line tension for most of my flying.  But like I say, what do I know.

Every thing I have flies on 4S.  That is one of the reasons I went with 4S on my SV-11.  It seems to work so I am happy. Another point I would like to make is that right now I am trying to learn the beginners pattern so I only fly for 4 minutes. The put back in the 4C 2800 battery was 1537 mah for a 4 minute flight or about 54% usage.  So when I want to move up from the beginners pattern I should be able to do 5.5 minutes without going to a bigger batter pack.

There's really nothing wrong with that set up. I'm not a fan of the pusher setup personally. I've tried really hard to like it. However it does things not within my muscle memory and I fly different airplanes so, like your great battery choice, I just stick with what works for me. I began E-CL using 3S batteries because that is what I had from my RC flying. Then I moved to 4s because everyone said they are "better" and lighter. They weren't when they are sized to fly the same mission. You can take two motors and two batteries with the same propeller and airplane and flying wise the performance is the same. Reason being is that he airplane performance is dependent upon the propeller being used. For instance the 3s 2200 MAH and the 4s 1800 MAH have exactly the same total energy content. They weigh within a few grams of each other and at the end of the flight power capacity ratio is he same. This result shows there is truly not a clear advantage of one over the other beyond the one that says, I used these because they are the ones like I already use. BTW, energy density is Watt hours per Kg.

Quote from: Mark wood on December 22, 2021, 10:05:19 AM
There's really nothing wrong with that set up. I'm not a fan of the pusher setup personally. I've tried really hard to like it. However it does things not within my muscle memory and I fly different airplanes so, like your great battery choice, I just stick with what works for me. I began E-CL using 3S batteries because that is what I had from my RC flying. Then I moved to 4s because everyone said they are "better" and lighter. They weren't when they are sized to fly the same mission. You can take two motors and two batteries with the same propeller and airplane and flying wise the performance is the same. Reason being is that he airplane performance is dependent upon the propeller being used. For instance the 3s 2200 MAH and the 4s 1800 MAH have exactly the same total energy content. They weigh within a few grams of each other and at the end of the flight power capacity ratio is he same. This result shows there is truly not a clear advantage of one over the other beyond the one that says, I used these because they are the ones like I already use. BTW, energy density is Watt hours per Kg.

What you said is all true.  However, if you are using a 4c setup and need more head room to maintain the set RPMs you can go to a 5c.  The other advantage of higher cell count is that it runs on lower current.  This means you may be able to use a smaller ESC and wires.  This might save weight.  Of course with really big airplanes (piped 60 size) 6c is required to keep the amp draw to a reasonable level.

Guys, thank you very much for the detailed answers, really appreciate this. If there are no objections from a topic starter, I will post some updates on the model once I build it - hope to prepare it till the next flying season.

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