All-New Freewing PJ50 Twin 70mm EDF Jet - Official Thread

[Enzo_K]

Not sure about that, but it makes sense that you could. On the other hand, the discharge amperage is still the same and I suspect you wouldn't save any time by doing that. If you discharge say a 6S 6200 mah, takes about 15 minutes or less. Hooking them up in parallel, now your discharging in effect a 6S 12,400 mah equivalent battery which would take like 30 minutes. I could be wrong, as I'm no electrical genius, but that's just what I'm thinking. Anyway, for me, this is a big time saver as I can discharge any batteries I didn't use at the field in my car on the way home. I've noticed that, although it is not a "balance" discharger, all 6 cells are still fairly close and then at home, I finish them off with a balanced storage charge.

I believe this is the correct statement. Consider putting two parallel batteries of the same size, C rating into a plane. Except for having to carry the extra weight, that plane should run for twice as long at the same throttle setting. If all you did was to run the throttle on the ground at mid-throttle (with some wind going into the intakes, it should run twice as long with two batteries as it did with one since the weight doesn't come into play when it just sits there. I guess you could do the same comparison when flying it although maintaining the exact same throttle for both flights and coming down with the exact same % left is difficult. Install two bats, but only hook up one, go fly. Next flight, replace the depleted battery, but now hook them both up and go fly. You'll likely double the flight time.

Just tested the parallel discharging method. Works just fine. Cells are fairly balanced after the cycle (this is where i was worried about).
Yes it did take double the time if you have 2 batts in parallel. Triple the time if you have 3.

The discharger gets the job down. Bluetooth connection could fail anytime though (once the bluetooth connection failed. the discharger WILL NOT CUT OFF. It will continue to discharge until unconnected). Give it some time to response after you hit start. Make sure it has the firmware updated.

I did more testing regarding the Bluetooth connection issue related to this discharger. Conclusion: It is not stable enough to leave it working on itown. The best if you calculate the time needed to discharge your batts. And set a timer on your phone.

[Enzo_K]

I don't about Mikey but both xWiper (banned now) and foamKrasher (from RCG) are one in the same. "Pitts" is NONE of the aforementioned. I think Pitts is just another older fellow who gets confused a fair bit. But like EvanD said, I'll cut him some slack (due to his "condition").


Thanks for the back up, Hugh. There are many of that kind at RCG and most of them are ignored as they have some serious mental health issues. In my last career, I've seen them in real life and now I see them all over the internet. That's life.

U are right Xviper. Thats the sad news for the internet. "don't have to worry about getting punched in the face" Instead of sharing experience and info with the community. A lot of people go online thinking others are just monkeys. Finding that last bit of self-esteem by assuming others are inferior. 🤨 I call it the "show off" syndrome.

[MeyerVW]

What a great flying aircraft. Like most foammies it is not a fan of crosswinds but does handle them if you have quick fingers. Flies very nice and fast at half throttle. To me it flies like the Me262. 6s 5000 100c spektrum battery. I got 3.5 min flight plus a few seconds but the battery was at 40% so its efficient. I went with the book for the throws at full but then I drop them 10%. full throw is 100% and then you can switch to 90 then 80 percent. Expo is at 30%. I flew around at 90% throws and its nice. Very responsive aircraft as well.

[GliderGuy]

25% throttle full dirty downwind might be a little risky for me. I normally keep it at over 40% on that downwind turn.
Could it be the aft CG you have made it "floaty"? Full flap feels too draggy for me. I actually land it better with half flap. Read the same comments from Soltproductions on Youtube the other day. I might lower the full flap setting to 20-24mm next time.

Hi Enzo, I still am balanced at the molded CG marks. Moving the CG back was a suggestion to possibly minimize the crow hop potential like it helps with the A-10.

I remeasured my flaps. Full deflection is less than the manual shows. This may be the cause of the tendency to float and why I can use less throttle in the pattern. I think I will leave it as is. It does land nicely “most of the time” when I don’t screw up.

-GG

PS I edited post #382 to indicate less than book max flap travel on my bird so as not to mislead others.

[Enzo_K]

Here are some shorter clips from the maiden flight. You can really hear the wing slicing through the wind in this one.

https://www.instagram.com/p/CadecoJujop/

[Enzo_K]

25% throttle full dirty downwind might be a little risky for me. I normally keep it at over 40% on that downwind turn.
Could it be the aft CG you have made it "floaty"? Full flap feels too draggy for me. I actually land it better with half flap. Read the same comments from Soltproductions on Youtube the other day. I might lower the full flap setting to 20-24mm next time.

[GliderGuy]

"Thrust Reverse, man, that's what life is all about" ................. bastardization from Phantom of the Paradise.

I totally agree. My comments are for those who don't yet have it. Fortunately, I have access to some LARGE areas of pavement, so not an issue for me. But....I can sure see where a short runway is gonna give someone fits.

-GG

[xviper]

If you don't slow down in the pattern and chop power short of the threshold YOU WILL LAND LONG!!!! She does not bleed energy very fast at all.

"Thrust Reverse, man, that's what life is all about" ................. bastardization from Phantom of the Paradise.

[GliderGuy]

After having now logged 73 flights on the PJ50, I have some well-healed information to offer....somewhat counter to my prior posts. Hey...I'm learning!

**Edit: Enzo’s comments down thread made me measure my flap travel. My max flap throw is LESS than the manual. I will leave it, but take this into consideration when reading my post below.

• I take it back...she DOES need aileron expo. In fact, 40% seems about right. Without it, she'd just too twitchy in windy conditions on final approach. Without expo, it is so easy to get into a rapid wing rock/over control situation on final when slowing down. Try it...you'll be pleased with how much this tames her down on final approach.
• I'm beginning to think that 5 or 10 mm aft of the Molded CG mark will be a better place for the CG. More than a couple of times, she's gotten into a bucking broncho type of crow hop like the A-10 does. Moving the CG back on the A-10 greatly reduces the crow hop for the A-10 (if not even eliminates it). I'm thinking the PJ50 needs a more aft CG to minimize the tendency. If you hit fast and hit a bump after touchdown or touch slightly nose wheel first...watch out! It has happened 5 times. UGH. Luckily, the lighter front end of the PJ50 doesn't put the same stress on the nose gear like the A-10 does. I have not see any damage from any of the 5 crow hop events. Just embarrassing to the max and had me scratching my head afterwards,
• Man...sooo important to really slow down in the pattern. I use about 25%** power on downwind...reducing to maybe 10%** on base and then 5% on final then I kill the throttle while still quite a short of the threshold. If you don't slow down in the pattern and chop power short of the threshold YOU WILL LAND LONG!!!! She does not bleed energy very fast at all even with full** flaps.

-GG

[Hugh Wiedman]

BTW Hugh, unloading batteries inside your truck could be dangerous. Especially when you are on the road. One of our club members had a 5000 5S, for his pattern plane, went off in the car. Lucky he tossed it out ASAP. But the toxic smoke stuck to the car for a while.

Now, while driving, I always keep batteries where they can be easily accessed. His words "if one goes off, toss it in someone else car! It's their problem now!" lol 😂

Great advice, thanks. I do keep it on the console next to me while driving so now I'll keep an eye out for the nearest car to toss out quickly! Had one go off in my home office/hangar one day when I first started flying and at the time I had no idea what a Lipo was or how dangerous it could be. It had puffed badly (an E-Flight battery of course) so I came up with the brilliant idea that I'd just pop it with a pin to release the pressure. Holy cow, flames and smoke belched out and I grabbed it by the leads, running through the house and threw it on the cement floor of the garage. It promptly burned a hole in the cement and took me a couple of hours to clear the smoke out of the house. Needless to say my CO was not a happy camper!

[xviper]

Hooking them up in parallel, now your discharging in effect a 6S 12,400 mah equivalent battery which would take like 30 minutes.

I believe this is the correct statement. Consider putting two parallel batteries of the same size, C rating into a plane. Except for having to carry the extra weight, that plane should run for twice as long at the same throttle setting. If all you did was to run the throttle on the ground at mid-throttle (with some wind going into the intakes, it should run twice as long with two batteries as it did with one since the weight doesn't come into play when it just sits there. I guess you could do the same comparison when flying it although maintaining the exact same throttle for both flights and coming down with the exact same % left is difficult. Install two bats, but only hook up one, go fly. Next flight, replace the depleted battery, but now hook them both up and go fly. You'll likely double the flight time.

[Enzo_K]

Not sure about that, but it makes sense that you could. On the other hand, the discharge amperage is still the same and I suspect you wouldn't save any time by doing that. If you discharge say a 6S 6200 mah, takes about 15 minutes or less. Hooking them up in parallel, now your discharging in effect a 6S 12,400 mah equivalent battery which would take like 30 minutes. I could be wrong, as I'm no electrical genius, but that's just what I'm thinking. Anyway, for me, this is a big time saver as I can discharge any batteries I didn't use at the field in my car on the way home. I've noticed that, although it is not a "balance" discharger, all 6 cells are still fairly close and then at home, I finish them off with a balanced storage charge.

I will give it a try once the discharger I ordered arrives. My idea is to have 2 dischargers unloading 4 packs. If I remember the parallel circuit correctly (man that was a long time ago, 5th grade? 11 or 12 years old), then yes it will take 30m to unload 2 of them 6s 6000 packs. I'm not concerned about the unbalanced discharge. Coz that's how the ESC discharge the battery. However, an unbalanced charge could be dangerous. That's why I said assuming they are left on the same voltage. Otherwise, the higher voltage batt will charge the lower voltage batt in a parallel circuit.

BTW Hugh, unloading batteries inside your truck could be dangerous. Especially when you are on the road. One of our club members had a 5000 5S, for his pattern plane, went off in the car. Lucky he tossed it out ASAP. But the toxic smoke stuck to the car for a while.

Now, while driving, I always keep batteries where they can be easily accessed. His words "if one goes off, toss it in someone else car! It's their problem now!" lol 😂

[Hugh Wiedman]

Thanks for the discharger info, Hugh. I wonder if I can discharge two or more same capacity 6s Lipos in a parallel circuit? Assuming all of them are left on the same voltage.

Not sure about that, but it makes sense that you could. On the other hand, the discharge amperage is still the same and I suspect you wouldn't save any time by doing that. If you discharge say a 6S 6200 mah, takes about 15 minutes or less. Hooking them up in parallel, now your discharging in effect a 6S 12,400 mah equivalent battery which would take like 30 minutes. I could be wrong, as I'm no electrical genius, but that's just what I'm thinking. Anyway, for me, this is a big time saver as I can discharge any batteries I didn't use at the field in my car on the way home. I've noticed that, although it is not a "balance" discharger, all 6 cells are still fairly close and then at home, I finish them off with a balanced storage charge.

[Enzo_K]

Just an idea, as I also used to discharge batts occasionally with a twin EDF, but then RudyD54 turned me onto the ISDT 200W Discharger. Takes about 15 minutes to discharge a 6200mah 6S fully charged to 3.84 volts per cell, or whatever you set it to discharge to. It can hook up to your phone and control it from there or just by hitting a couple buttons on the unit itself. Discharges 2S-6S up to 25A/200W, or again whatever you set it to do. Comes with a fan and saves me tons of time if I don't discharge a battery to a low enough storage value during flying or sometimes have to leave with a fully charged battery (yes, that's sacrilegious). It doesn't balance discharge but you set the level you want to discharge to, then at home I put the batts on my charger to balance storage charge to 3.85 V per cell. Can get it at multiple outlets for about $79. I can charge up to 8 6S batts with my current set-up, but unfortunately the discharge function I have is lame at .5Amps and just about the time "hell freezes over" is when it's finally done! Was thinking about getting a 2nd one but so far one has been sufficient.

Now I can't discharge 10 in 20 min like you do with the Mig, but I'll discharge some at the field while packing up, put some on in the truck on the way home so by the time I home, I'm done. Also didn't like putting "extra hours" on any of the EDF's or ESC's.

Thanks for the discharger info, Hugh. I wonder if I can discharge two or more same capacity 6s Lipos in a parallel circuit? Assuming all of them are left on the same voltage.

[Enzo_K]

Merged the message up. IDK how to delete a reply, and it requires text. LOL. So here is another thing I always do when adjusting surface travels.

Prioritizing the radio travel range near 100% is the goal. Too low from 100% you lose all the resolutions of the servo. Too high from 100% you over load the servo. My preferred range on the radio, to achieve the physical travel I want, is from 85% to 115%.

And if you have too much travel. Always move the linkage to inner holes on the servo arm first. This will put less pressure/torque on the servo. Thus longer service time.

[Enzo_K]

Hi Enzo,
Thanks for the write-up.

I would suggest if you find the rudder overly sensitive, move the pushrod to the outer hole on the horn. When the pushrod connection is on the hole nearest the rudder (inner hole), the servo will move the control surface the maximum amount.

Connecting the push rod to the outer hole of the horn….the servo moves the control surface a lesser amount.

The above assumes you leave the pushrod connected to the same hole on the servo horn.

The least possible movement is attained with a pushrod connected to the servo horn’s inner hole while connected to the control horn’s outer hole.

Don’t believe me? Experiment. The theory is based on the arc radius from the pivot point….which is the base of the control horn or the center set screw of the servo horn.

-GG

Thanks for the explanation. But Yah, I was talking about the servo arm. You can see the photo attached was the servo arm, instead of the rudder control horn.
I edited the post if it was causing confusion.
And the rudder control horn already came with the linkage attached to the outermost hole. So I didn't bother changing it at all.

[GliderGuy]

Hi Enzo,
Thanks for the write-up.

I would suggest if you find the rudder overly sensitive, move the pushrod to the outer hole on the horn. When the pushrod connection is on the hole nearest the rudder (inner hole), the servo will move the control surface the maximum amount.

Connecting the push rod to the outer hole of the horn….the servo moves the control surface a lesser amount.

The above assumes you leave the pushrod connected to the same hole on the servo horn.

The least possible movement is attained with a pushrod connected to the servo horn’s inner hole while connected to the control horn’s outer hole.

Don’t believe me? Experiment. The theory is based on the arc radius from the pivot point….which is the base of the control horn or the center set screw of the servo horn.

-GG

[Enzo_K]

Here is a sketch of what I mean by relocating the control box/blue box. Instead of facing upward and all the way front in the battery area. Move it back to where the wing sits. And facing downward. This will make connecting/disconnecting wings and those wires much easier.

When you try to disassemble the wing. You are most likely gonna have the plane inverted on a stand. By moving the blue box here. You will have access to all the connections when you pull the wing off.

[Enzo_K]

This is a beautiful business jet based on the GS 550. I'm here to share my experience with it. Hope this could help with some of you out there still looking into buying one of these. Or those of you who already ordered one but haven't put it together.




List of electronics onboard:
RX: Spektrum AR8360T SAFE&AS3X receiver.
Steering Gyro: Assan AG61 steering gyro.
An additional Freewing LED control box. (For separate wing root landing light control.)

Assemble:
It will take you roughly 1.5-2 hours to put everything together. Unlike some previous Freewing/Flightline products. The PJ50 came with all the control linkages preinstalled. I only needed to do some minor adjustments to the elevator. Being such a large model, another person's help could come in handy.
The fuselage, however, will need to be glued together. My advice is, after applying glue, leave it standing on its nose for over 24 hours.



Minor modifications:
1. I moved the control box afterward, to accommodate the AR8360T receiver. If you do this, it will be harder to reach the cable connected to the control box. I'm transporting this jet without disassembling it. So I don't have to worry about disconnecting cables every time. For easier disconnecting cables. I've recommended the manufacturer relocate the control box right underneath the wing. (I drive a 2015 Audi Q7. For those of you wonder if it gonna fit inside your car)
2. The nose suspension feels too stiff on mine. I cut off 3-4 coils of the stock spring. And added another softer piece of the same length in it.
3. Moved the Rudder link 2 holes inside on the servo arm. The recommended travel for the rudder is too much for my liking. And it is also dangerous during the landing phase. I will talk about this in the flying section of this post.


Radio setting:
Aileron: 100% L/R with manual travel. 23mm L/R. 20% expo
Elevator: 100% up/down with manual travel. 24mm up/down. 20% expo
Rudder: 115% L/R with the 3rd hole on the servo arm. 27mm L/R (So you have a decent taxi turning radius and not too much rudder). 30% expo
Flap: Setup per manual. 15mm half, 29mm full.


CG.
The factory mark underneath the wing feels just right. I fly with an SMC 8100mah Lipo. Weights 910g.

Flying:
Cruise around: This jet is a really efficient flyer. It will fly around with about 50% throttle. Plenty of power. A 6000mah battery should last more than 4m30s for any style of flying.
Taking off: The wing load is around 110g/dm^2. That means it gets up in the air pretty quick. Took about 80-100ft on our geotextile runway with full throttle and half flap.
Aerobatics: The airframe will handle any mild aerobatics just fine. Loops, rolls, inverted.
Landing: I've landed it smoothly in 10-15mph of crosswind (35-45 degrees down the runway). It handles the wind just fine. Also, half flap works better for landing. The full flap feels too draggy for me. U will need to carry a good amount of throttle if you wish to land smoothly with full flap. The strange part is, when landing with a higher AOA, this jet doesn't like rudder at all. Just a little rudder will swing/bank the wing around for you. So I lowered the rudder surface travel to 27mm. And dialed in 30% expo.
Maiden flights:

Other things to watch out for:
1. There is a piece of screw right next to your nose gear, steering servo, and nose light cables. Over time it could damage the wire. I wrap the screw with a piece of thick tape.
2. The LED between two main wheels has exposed wires on mine. It could be a problem if you fly this jet in some confined Area. For example, our runway does not drain very well. And it gets all muddy after the rain. Those exposed wires are not gonna do well with some sodium and water. I wrapped the exposed wire with electrical tape. Then sealed it with some foam glue.

[GliderGuy]

Franknitti, You should design sailplane trailers!

Nice work.

-GG