I was advocating actually measuring servo current since we can so easily now.
Using the technique above, I have found binding where I thought I had none.
I also set my programmable BEC's to 6V or so which gives headroom for the receiver.
I have had gear hang up on retract but the BEC powered through it rather than running down like a battery.

Can anyone confirm the correct CofG for the 35e version?

Originally Posted by jonjon69

Can anyone confirm the correct CofG for the 35e version?

The CG should be between 2 and 2 1/2 inches from the leading edge of the top wing. The manual indicates 3 1/2 inches which is wrong.

Excellent. Thank you so much! That explains alot. My maiden was just about a disaster. I was able to bring her down in one piece.

using the ZS4025-16 has anyone gone to a 7 or 8 cell setup? Thanks, Joe

Originally Posted by sarkantyu

using the ZS4025-16 has anyone gone to a 7 or 8 cell setup? Thanks, Joe

Not me...it's designed for 6S...

SteveT

Originally Posted by sarkantyu

using the ZS4025-16 has anyone gone to a 7 or 8 cell setup? Thanks, Joe

I have been flying mine on Hyperion 4200 7s for a year now and I love it. The samson is finnally delivering te performence I have been looking for. After a lot of experimenting with props I found that this set-up works best with a Turnigy 19 X 10 E prop. Tremendous power and with a little throttle management I get solid 6 minute flights. The 7s 4200's weigh the same has the 6s 5000's.

Richard

Thanks ,just what i was looking for .Can someone point me to the mods this plane needs before i start building it.Joe

I have read most of this thread (not all, it's too long!), and I'm hoping for some good advice...

My Samson 70 is arriving today, and I'm wondering if I can use a Hacker A40-12L that I already own on it. I plan to use a 5S 5000 pack, and I'm not completely sure what ESC I should buy. (It's probably obvious by now that I'm relatively new to the hobby -- started 6 months ago.) I don't need crazy performance, but can someone tell me if this setup will be too underpowered?

Originally Posted by timlake

I have read most of this thread (not all, it's too long!), and I'm hoping for some good advice...

My Samson 70 is arriving today, and I'm wondering if I can use a Hacker A40-12L that I already own on it. I plan to use a 5S 5000 pack, and I'm not completely sure what ESC I should buy. (It's probably obvious by now that I'm relatively new to the hobby -- started 6 months ago.) I don't need crazy performance, but can someone tell me if this setup will be too underpowered?

I think it would be... The suggested Hyperion motor is closer to the A50-16S as far as power and battery size (6S)....

SteveT

timlake,
Welcome to the hobby and congrats on the Samson 70e purchase. I'm on my second one already and the first one delivered more than 50+ enjoyable and somewhat reckless flights!
With a Hacker A40-12L and 5s5000 batts, the plane will certainly fly, you will not have unlimited vertical, but the plane will certainly cruise nicely and do loops and rolls if you let it dive a little first.
Don't take my word for it - electrics are easy to figure out:-
Use this free website at http://www.ecalc.ch/motorcalc_e.htm
First, look at Hyperion's data sheet on aircraft-world.com to see what the factory recommendations are, these will be your baseline requirements. You will see that the airplane designers recommend a Hyperion 4025-14 to be used with a 16x10 propeller if you're using a 6s battery.
Second, punch in these parameters into the ecalc program. You will see that the stock setup will deliver about 1094W to move this 8 lb. plane.
Third, punch in the parameters of your Hacker A4012L motor into the assumptions at 5s to see what the power output would be. I just did that and the program says that the motor would deliver 840W, which is about 20% less power than recommended but it would certainly fly. (Rule of thumb is 50W/lb will take off; 100W/lb would fly like a sport aircraft; 200W/lb would let you zoom straight up!)
Now you could choose to use higher voltage (but going to 6s) or use a bigger prop (e.g. 17x10 or 16x11) but be aware that the Hacker motor has a maximum operating amp limit of 45-55amps beyond which it would let out the magic smoke...practically speaking you won't be a full throttle all the time so there is some cushion there. The size of the ESC should be slightly larger than the maximum amps that you would draw. (The castle creations 75amp would be plenty in this case, although you might want to consider the 100amp because it's not much more expensive nor heavier...)
Fourthly, now that you are happy with the compatibility of the power system you would then have to check if the dimensions of the Hacker would fit inside the cowl easily (unless you don't mind cutting the nice fake engine a little)
If it were me, if I already have the motor AND the battery then I would certainly give it a go; if I only have the motor, then rather than spending more $$ on another battery which is not ideal for the job anyway; I'd get a more advanced motor capable of more volts and amps...this plane is so pretty I think it deserves it Having said that, after the first ten flights or so on my first 70e I notice that most of the time I would just be doing graceful slower maneuvers which 100W/lb ought to be sufficient...My stock settings were plenty powerful enuf and I was even thinking of adding a 1.5lb sound system into the belly of the plane. (I think this model needs more presence, not acrobatics but that's just me.
I would also highly recommend having an experienced friend to double-check the plane before maiden (whether or not CG is at the right place, controls are not reversed, ailerons aren't loose, radio antenna is properly oriented, actual amps and volts are close to what the computer predicted, etc...) Use a Loc8tor would allow you to salvage parts should the unthinkable happen.
Hope that helps...
Godspeed!

And don't forget to reinforce the wood where the landing gear is attached to the fuselage unless you plan on having perfect landings every time!

Wow... What a thorough explanation -- thank you! I actually ended up buying the Hyperion ZS4025-16, CC 100 amp ESC, and a 18 x 10 APC electric prop. I plan to use 6S Lipo. Any suggestions on C rating? How do I choose a spinner? When I plug in values into ecalc, I still get less than 1000W... Is this ok?

Originally Posted by timlake

Wow... What a thorough explanation -- thank you! I actually ended up buying the Hyperion ZS4025-16, CC 100 amp ESC, and a 18 x 10 APC electric prop. I plan to use 6S Lipo. Any suggestions on C rating? How do I choose a spinner? When I plug in values into ecalc, I still get less than 1000W... Is this ok?

For the perfect spinner for this plane check out this post...

SteveT

That looks great! How can I be sure that adapter nut will fit on the prop adapter that came with my motor?