Official Roban 120mm A-10 Warthog V2 EDF Jet Thread

[gravity tester]

Hi Jink-
I am so far from an expert I can't even see the "E" but I offer this for what it is worth since they are similar airframes. Like you, I am running 2 LiFe batts for my Rx in the CGRC (Spektrum 2310 Powersafe 12 ch.) but also running a separate 7.4V batt for the landing gear which are older model Century Jet (R.I.P.). Not sure what D&L requires for power? I found I needed the extra nose weight anyway so it is not a burden. Bottom line is I have 7 batteries total to get the pig airborne.

I charge those LiFe at 1c as I do all of my LiPo's for my other planes, unless I am really in a hurry. Then I charge at 1.1. Ha ha. IMHO, there is just no need to force feed the battery any harder. The time savings of a few minutes of my day charging at 2.0 C for example, is not worth the overall risk. With a couple packs in rotation, by the time I am ready to fly again, so are the batteries if that makes sense. I store the LiFe's at or at least "government work close enough" to the 3.3V that OV10 showed above.

As far as charging, my main charger now is a 1000W PowerLab 6 Touch. This thing can tie my shoes and make me coffee and it probably has features I don't even know about yet but I like the battery parameter history and the different geeky charge details it records, even if I don't know what they mean. It also has a Bluetooth connection to an app on my phone that says "...Hey idiot, your batteries are done..." I use it with a parallel board and can charge 4 batts at once but normally only charge 2 at a time so I don't tax the solar system at our field. 2 6S 5000's at a normal "fill up" takes 30 minutes or less - about the time the pizza arrives. I don't use the RFID "bump tags" the charger comes with. Honestly, they are really cool but the total time savings is about 7 seconds since the batteries are stored in the charger memory. A couple button presses and you are off.

Hope that helps. PS. My A-10 obsession probably requires professional help. I forced (sic) myself to buy a T-33 and also have a F-100 "Hun" on order so I could make myself feel normal.

Cheers.

[jinkrat4791]

I would have been lost completely when i picked up electric flight had it not been for rc groups. And I just recently joined Squawk when I found the thread on the A-10 I happened to be building. Before that I've read a thread here and there when it was something that interested me but never joined and actually posted anything until I bought my first electric airplane. Had this been a big twin gas powered bomber with air retracts I would have been in completely familiar territory. Truthfully, If I hadn't been obsessed with the idea of building big A-10 for the last 20 years, I would have waited a while until I had more experience with electric power systems. A turbine model is out of my budget range and even more intimidating than taking on a big edf version. The thing is, I enjoy projects like this, I don't get very much pleasure out of pulling an ARF out of the box on Monday and having it ready to fly by the weekend. Those are just my models that give me something to fly while I work on something like this. Usually one of my big projects like this ends up getting sold. One I sold about 15 minutes after the maiden flight. Others after 30 to 50 or so flights. I save every invoice for every single thing I buy for these projects in a file, even if it's a couple bucks for a handful of button head screws or something like that. I've actually made money on every one I've sold because I've never tried to sell one, I end up getting approached by someone interested. I give em a price and show my documented investment and I add in what I want for my time invested. Either they are willing to pay or I wait for the next person to come along. Thats the only way I can fund projects like this repeatedly. This one is comming out of pocket completely because I took about a 5 year break in building large models due to a nasty break up between my ex an I. We we not mairried but our finances we're thououghly entangled after living together for 15 plus years. Had to sell the house and of course my workshop along with it. This is the first giant scale airplane I've ever built on a dining room table and that has been a challenge all in its self. With getting into electric I thought I would get into 3D flying, and I have gotten fairly decent in the past year but my passion in this hobby is scale military aircraft. Before the A-10 it's been ww2 fighters and bombers. This is my first modern warbird. And I think this is going to be my nitch for a while. I'm already trying to find a good set of plans for a balsa built F-15 in a PDF file format so I can resize them. Haven't had much luck with that so far. Anyhow, these forums have been a great help and I've enjoyed connecting with modelers all over the world. I wish I would have gotten involved with them sooner.

[jinkrat4791]

Seeing that this model is going to take 6 batteries to make her go, (4 lipos and 2 life) I was planning on buying another charger like I have, or possibly buying a nicer charger all together that will charge at least 4 batteries at once. I'm leaning towards just getting same because it will probably save me a couple hundred dollars. But if I decide to get a nicer charger I'd like to have some opinions from some of you guys with more experience as to which one I should be looking at. I know my charger I have now will charge up to 6s and I believe it's 200 watts per port. Thanks again

[OV10]

jinkrat4791 I believe most if not all chargers have to be told what type of battery your hooking up.
Once told then the more expensive ones will know cell count and so on.
Just keep asking questions here at the Squawk, one of the best forums to learn on and I have yet to see where someone didn't have an answer for the inquiring mind.
Since you are venturing forward with this beast A-10 I would strongly recommend that you invest in a stronger 6S charger that has a minimum of 200W per port

[jinkrat4791]

Ohhhhh.............In your prior 2 posts you did not ask about specific storage voltage until now because I'm guessing that you don't trust your charger.
So here is a list of the different Lithium products with their voltages for Max charge/discharge, nominal and storage levels.

..................…..LiPo……LiFe……LiLo…..LiHV

Nominal……...3.7...…..3.3...…...3.6...…..3.8
Max...………...4.2...…..3.6...…...4.1...…..4.35
Discharge...….3.0...…..2.0...…...2.5...…..3.0
Storage...…….3.85...…3.3...…...3.75...…3.9

Any good quality charger usually has a chart similar to this in the manual.

Thank you, that's what I needed to know. My charger is the Hitec RCD that only charges two batteries at once. It was only $99 but has worked well for me so far. But the info you just gave me is not in the manual. I can't see where the manual that came with it is of any use to a noob. It just confused me more than anything. On top of that I don't have any flying buddies that I've been able ask questions because we lost our field almost a year ago and our club has pretty much disbanded. At that time there wasn't but one person flying electric and to be honest he was the official club prick, I wouldn't call him if my life depended on it. But thank you for the info. That was what I was looking for. And I think my charger is relatively basic, it will not recognize what type of battery you hook up it will only tell you if you have the charger set wrong. You have to manually input the type battery, charge current, and number of cells.

[OV10]

My charger does for the most part. The question that I'm asking is does it need to be stored a certain voltage and if so what is that voltage. Thanks

Ohhhhh.............In your prior 2 posts you did not ask about specific storage voltage until now because I'm guessing that you don't trust your charger.
So here is a list of the different Lithium products with their voltages for Max charge/discharge, nominal and storage levels.

..................…..LiPo……LiFe……LiLo…..LiHV

Nominal……...3.7...…..3.3...…...3.6...…..3.8
Max...………...4.2...…..3.6...…...4.1...…..4.35
Discharge...….3.0...…..2.0...…...2.5...…..3.0
Storage...…….3.85...…3.3...…...3.75...…3.9

Any good quality charger usually has a chart similar to this in the manual.

[jinkrat4791]

The underlined question would be yes if you are concerned (as you expressed earlier) with getting long term usage.
Again, being that it is of the Lithium platform of batteries any smart charger will take care of your maintenance needs for the LiFe

My charger does for the most part. The question that I'm asking is does it need to be stored a certain voltage and if so what is that voltage. Thanks

[OV10]

I'm fairly new to electric flying, I'm just getting to the point where I feel like I fully understand lipo flight packs. Does a life pack have to be stored at a certain voltage like a flight pack. I just don't know what to do to do to maintain them

The underlined question would be yes if you are concerned (as you expressed earlier) with getting long term usage.
Again, being that it is of the Lithium platform of batteries any smart charger will take care of your maintenance needs for the LiFe

[jinkrat4791]

jinkrat4791
Hello Jink………...What is the contradictory info that you are reviewing regarding the LiFe (short for LiFePO4 or Lithium-iron phosphate) battery?
The Lithium battery products have been established on the market long enough now that the info on them is fundamentally established and consistent.
All Lithium batteries safe charge characteristics are nominally @ 1C which in the case of your 2200mAh example would be 2.2Ah.
All Lithium products are not meant to be "fully discharged" ( 0 volts). In the case of the LiFe, it's nominal operating voltage is 3.2Vdc with the minimum safe lowest discharge voltage is 2.8Vdc.
The maximum charge voltage is 3.6V. Those above voltages are already part of the programmed LiFe parameters in any modern charger.
Set your charge amperage for 1C ( 1 x the A/hr rating) and you'll be good to go. This applies for any Lithium product for a safe reliable charge.
Best regards,

I'm fairly new to electric flying, I'm just getting to the point where I feel like I fully understand lipo flight packs. Does a life pack have to be stored at a certain voltage like a flight pack. I just don't know what to do to do to maintain them

[OV10]

I have a question, this is the first model I've ever used life batteries for powering my receiver and retracts. I've searched for information on charging and I've read a lot of contradicting information. They are 2s 2200 mah spektrum life batteries. What current should I set my charger on to charge. Ive read different posts saying .5 and others up to 1.5. I want them to last and stay healthy as long as possible. And do they need to be fully discharged before charging again. Basically I know nothing about them at all so any info will help. Thanks

jinkrat4791
Hello Jink………...What is the contradictory info that you are reviewing regarding the LiFe (short for LiFePO4 or Lithium-iron phosphate) battery?
The Lithium battery products have been established on the market long enough now that the info on them is fundamentally established and consistent.
All Lithium batteries safe charge characteristics are nominally @ 1C which in the case of your 2200mAh example would be 2.2Ah.
All Lithium products are not meant to be "fully discharged" ( 0 volts). In the case of the LiFe, it's nominal operating voltage is 3.2Vdc with the minimum safe lowest discharge voltage is 2.8Vdc.
The maximum charge voltage is 3.6V. Those above voltages are already part of the programmed LiFe parameters in any modern charger.
Set your charge amperage for 1C ( 1 x the A/hr rating) and you'll be good to go. This applies for any Lithium product for a safe reliable charge.
Best regards,

[jinkrat4791]

I have a question, this is the first model I've ever used life batteries for powering my receiver and retracts. I've searched for information on charging and I've read a lot of contradicting information. They are 2s 2200 mah spektrum life batteries. What current should I set my charger on to charge. Ive read different posts saying .5 and others up to 1.5. I want them to last and stay healthy as long as possible. And do they need to be fully discharged before charging again. Basically I know nothing about them at all so any info will help. Thanks

[jinkrat4791]

Inquiring minds and all...Here is one of many explanations that are out there: https://www.youtube.com/watch?v=E-qcZahbxbI

Cheers,
Dan

PS. I should add that I was a miserable Boy Scout. The notion of me trusting a $3000+ airplane to a knot I tied in the ceiling is more nerve trashing than the maiden.

That whole set up looks to be more trouble than it's worth, I built basically a large version of a balancing stand similar to like the old Great Planes balancer. I changed a few things making it more suitable for a giant scale aircraft and it worked great. you could set the airplane right side up or upside down. With a model like Hog you would set it right side up. Then you can see how the CG changes as you cycle the gear. I gave it away because I haven't built a big model like this in quite a few years. I'll be making another one for use on this project and future projects as I've seen to have been bitten by the large jet bug. I haven't seen the guy in quite a while but I'll see if I can get him to send me a pic of it and I'll post it for you

[jinkrat4791]

I've used them in the same manner in my P-38 for a couple of years and had no issues. I'm running Spektrum electronics. I think you're good.
Bob

thanks Bob, I'm running spektrum as well, I thought it would be ok but I wanted to hear that from someone with actual experience with that type of set up. With this much money in an airplane I don't plan on assuming anything. Thanks again

[buffetbob]

Ok, so I have a question, I've always heard that using digital and and analog servos in the same aircraft will cause problems. I I've never been clear on exactly what kind of problems but I've just avoided it. In this A 10 I went analog for all control surfaces but I have two micro digital servos one controlling the nose gear door and steering. Neither are connected to the receiver. Both are connected directly to the retract controller. They are even running off a separate life battery that only runs the retract controller and the lighting systems. I don't see how they could cause me any problems but i may be wrong. I'd rather ask a question than risk a problem so any opinions are appreciated

I've used them in the same manner in my P-38 for a couple of years and had no issues. I'm running Spektrum electronics. I think you're good.
Bob

[gravity tester]

And I must be really dum because I don't even know what Vanessa Rig is. But now I have to know, and thanks for that link

Inquiring minds and all...Here is one of many explanations that are out there: https://www.youtube.com/watch?v=E-qcZahbxbI

Cheers,
Dan

PS. I should add that I was a miserable Boy Scout. The notion of me trusting a $3000+ airplane to a knot I tied in the ceiling is more nerve trashing than the maiden.

[jinkrat4791]

Hi Jink-
Original scale wheels are 94mm and 6.1oz each with axle. The new ones with brakes are from Xicoy and they are 90mm and 8.2 oz each with axle. So I lose 4mm (not awful from a scale perspective) and gain 4.2 oz overall. I also lose about 4mm in width. Gaining the ability to stop before the plane rolls to Arizona: Priceless. Not having to hog out any of the sponson to fit the new wheels: Heaven. I can live with someone telling me my wheels look a little small.

Here is a link to the wheels: https://www.xicoy.com/catalog/produc... away with mq0

I had new axles machined to fit my struts. The stock axles from Xicoy were too short. I did notice that Xicoy makes a 100mm wheel with brake as well. That might be a better look for your Roban since it is a slightly bigger scale than the CGRC.

FWIW, my CG calculations were done with scales and gear extended. I am too dumb for a Vanessa rig. Point being, I may need to adjust for the extra 4 oz. in front of the CG in flight. Better than behind it for sure, but still an adjustment.

Cheers,
Dan

ok, so brakes have come a long, long way since ive actually looked at a set for past prproject project, that has to be close to four yrs now. They used to add lbs not 4 or 5 oz. I do hate losing my scale wheels. And the roban has a little rotation issue on take off. Could probably still use the shorter mains. It would give it a slightly more positive angle of attack and every little has to helps with that. I may just have to call Mitch. Get him to make me a set. I could even get away with using a longer nose wheel strut and that would make a big difference with the shorter mains as well. Thanks landing gear is just so far behind the CG. A little more positive angle of attack on take off definitely won't make it any worse that's for sure.

And I must be really dum because I don't even know what Vanessa Rig is. But now I have to know, and thanks for that link

[gravity tester]

Hi Jink-
Original scale wheels are 94mm and 6.1oz each with axle. The new ones with brakes are from Xicoy and they are 90mm and 8.2 oz each with axle. So I lose 4mm (not awful from a scale perspective) and gain 4.2 oz overall. I also lose about 4mm in width. Gaining the ability to stop before the plane rolls to Arizona: Priceless. Not having to hog out any of the sponson to fit the new wheels: Heaven. I can live with someone telling me my wheels look a little small.

Here is a link to the wheels: https://www.xicoy.com/catalog/produc...so0rfharqjqmq0

I had new axles machined to fit my struts. The stock axles from Xicoy were too short. I did notice that Xicoy makes a 100mm wheel with brake as well. That might be a better look for your Roban since it is a slightly bigger scale than the CGRC.

FWIW, my CG calculations were done with scales and gear extended. I am too dumb for a Vanessa rig. Point being, I may need to adjust for the extra 4 oz. in front of the CG in flight. Better than behind it for sure, but still an adjustment.

Cheers,
Dan

[jinkrat4791]

Hi Jink-
My set of pylons is molded plastic, not 3D printed so I am not sure about that deal. The only thing I ever got from Chris G. that was 3D printed was a one-off copy of the ACES II seat that he had sitting in a spare parts box. I am not sure if he ever got around to molding it for production. Anyway, it's been a while but I vaguely remember buying a set of the pylons plus some other molded parts (cannon, nav light frames, various bumps and blisters, etc) as a package for around $100.

Yes, it did end up a little heavier than I thought it would at 34 lbs, but I am very happy with the performance on the JF110's (10s) - it moves quite well and very scale. Doubt I could hover, but I was never really all that good at it anyway. ;-) Kidding, of course. Anyway, officially I have 2 flights on it. The issue for me last season was more scheduling between work and access to fields where I feel comfortable flying it. The closest one is an hour and a half away in Muncie (AMA HQ). My local club is close but not really a place I would consider. Beautiful grass runway but the pucker factor curve is too steep for me with trees, overall visibility and runway length. A better pilot might have no issue. Me, I'm not that dude. I do belong to the Rosewood RC club as well, the site of the EDF Jet Jam but that field is 2+ hours away. Bottom line is a trip to the field to fly the beast requires some more complex logistics than my FW version.

She's flyable, but I am currently changing out the landing gear controller to an updated, more reliable version from Dave's RC, adding brakes (yay!) and changing out the nose gear servo. I have burned out 2 micro digital servos (Savox). The gear is free and doesn't bind at all. I think the smaller digital trying to hold center is the issue. Anyway, I am switching to a larger analog servo but it requires a little mount surgery. Also adding a few more scale details (bomb lugs, weathering). I'll be ready whenever this home detention thing is lifted and I can get to the field.

Dan

I feel you with the field choice situation. Our club had a nice field, plenty of room to fly mine. It was in the industrial park area of my town. About 9 months or so ago the owner of a fuel distribution company about half a mile from our field complained to mayor of our little town claiming if one of our little airplanes were to hit one of his giant metal gas storage tanks that it would surely cause a catastrophic explosion. Seeing that they operate on the 'good ol boy system' here our field was shut down the next day. We have been looking for a suitable spot for another field but haven't been able to work anything out as of yet. Most of the members have started selling off all their planes so I believe the club is just going to disband.
Fortunately for me I have a 40 acre field right across the street from my house and I keep a 100ft runway cut year round. I can fly all my other planes there but there's no way I'd fly something like my a 10 there. I have permission from the land owner but he told me not to turn it into a club type situation or I'd get the boot. I have a friend or two I let come fly with me but strictly electric planes only. I have to find a good spot to maiden my A 10 but there's no rush. I can probably do it at the little local airport which would be ideal. I do hope we can pull the club back together but it doesn't look good

And BTW, what brakes are you looking at and how much weight do you think it will add, I was going to try mine without brakes at first. Weight being the main issue, cost being the second. On grass it won't be an issue, but a paved runway, it would probably roll into the next county. I'd really like to have them though.

[gravity tester]

Hi Jink-
My set of pylons is molded plastic, not 3D printed so I am not sure about that deal. The only thing I ever got from Chris G. that was 3D printed was a one-off copy of the ACES II seat that he had sitting in a spare parts box. I am not sure if he ever got around to molding it for production. Anyway, it's been a while but I vaguely remember buying a set of the pylons plus some other molded parts (cannon, nav light frames, various bumps and blisters, etc) as a package for around $100.

Yes, it did end up a little heavier than I thought it would at 34 lbs, but I am very happy with the performance on the JF110's (10s) - it moves quite well and very scale. Doubt I could hover, but I was never really all that good at it anyway. ;-) Kidding, of course. Anyway, officially I have 2 flights on it. The issue for me last season was more scheduling between work and access to fields where I feel comfortable flying it. The closest one is an hour and a half away in Muncie (AMA HQ). My local club is close but not really a place I would consider. Beautiful grass runway but the pucker factor curve is too steep for me with trees, overall visibility and runway length. A better pilot might have no issue. Me, I'm not that dude. I do belong to the Rosewood RC club as well, the site of the EDF Jet Jam but that field is 2+ hours away. Bottom line is a trip to the field to fly the beast requires some more complex logistics than my FW version.

She's flyable, but I am currently changing out the landing gear controller to an updated, more reliable version from Dave's RC, adding brakes (yay!) and changing out the nose gear servo. I have burned out 2 micro digital servos (Savox). The gear is free and doesn't bind at all. I think the smaller digital trying to hold center is the issue. Anyway, I am switching to a larger analog servo but it requires a little mount surgery. Also adding a few more scale details (bomb lugs, weathering). I'll be ready whenever this home detention thing is lifted and I can get to the field.

Dan

[jinkrat4791]

GravityTester, I remember early in the other thread on rc groups that Chris 3D printed a set of weapons pylons for a guy's roban a 10. He may still do small stuff like that from time to time. I was just going to make my own out of foam and glass but I wouldn't be against spending a little money for his cause they are already all detailed out with panel lines and rivits and such. Can you tell me how much you paid for your pylon set just so I have an idea of about what they would end up costing me?

Thanks,
Jink