How low can you go?

[im4711]

Most blades possibly would do OK. On 500 size machine I tried at least 8 different sets ending up with Rail and Switch that allowed me to bring head speed down to 1050 rpm for cruising around and 1350 rpm for slow motion 3d. All others had issues in the 3d maneuvers.

Most often limitation simply is tail authority. Up to some level you can compensate by smooth collective input. However that smooth you may forget in a critical situation and the tail will spin around. So you better know how to handle such situation
Lowest on my HD750 was about 760 rpm for cruising around and 850 rpm for 3d. Again -> when you are down even below the 800 rpm there you need to be extremely careful with collective. On the HD750 I did not try that many other blades since the price for blades is a bit to high to get all different brands.

2015 IRCHA HD500 Low Headspeed (3 min 8 sec)

[f8fbc]

Originally Posted by bikneli

Have you been reading about the VTXs? They look to be very good at
LHS. There is a video in the Mikado section w. them on a 690.

I will be trying at least a pair.......hopefully on the market soon.

Saw those, and would definitely like to try them when they are available. They sure look nice.

[f8fbc]

Originally Posted by im4711

Most often limitation simply is tail authority. Up to some level you can compensate by smooth collective input. However that smooth you may forget in a critical situation and the tail will spin around. So you better know how to handle such situation

Feel you on that, I have had the same experience, almost crashed a couple of times when the tail went in an unexpected direction.

I am going to try some longer tail blades. When I get a chance I may change the gearing on the tail. That's one nice feature of Synergy Heli's.

[im4711]

Sure longer tail blades or other tail pulley increase tail authority and work great for some low head speed flying. Downside -> you are tight into low rpm since the noise level would be annoying once speeding it up. My machines I never want for only low rpm. The 750 runs a full range from 850 all the way to 2200 rpm with 12s. No changes required. Thats what I like on the machine. My 500 is running from 1050 all the way to 2600 rpm and again - no change required.

Once below 1350 rpm on a 500 you will have a hard time finding a tail pulley you need for full tail authority. Also below the 800 rpm mark on the larger machines. Thats where you feel it the hard way. Above you normally do OK and can fly 3d.

[KSKen]

I know this is an older thread but if you can retro a 3-bld tail and run the same size tails X3, it's amazing what happens at low HS.
I did this on my protos Max 800 and 770 and 3 115's have tremendous authority over 2 at low speed.

[im4711]

I agree - switching from 2 bladed tail to 3 bladed will increase tail authority a lot. That way you may only end up having lift and head stability as factor in order to bring the rpm down.
On the HD500 my lowest rpm to lift off was about 1050. I was able to flip at 1300 - 1350. However I also flipped - went inverted and switched down to 1050rpm again. Below 1000 I tried but did not generate enough lift to keep it in the air. If a bit of a wind gust got the machine it was right back on the ground. So 1050rpm was my magic number for flying and 1350 for arobatic (simple flips, rolls, piro flips ... nothing agressive).

[sawacs]

Having recently test flown my Trex 600L, I have dialed in the following governed rpm:

1390
1210
970

Rail 606mm mains
90mm tails
6S 5200 pack
Max pitch 10 degrees

1390 and 1210 are perfectly flyable with good collective management. I use the 970 rpm setting to practice fake autos and it works great. The 970 rpm will hover out of ground effect and climb out slowly but I have not tried flying around.

[Keyrigger]

I have been working with my MD-7/8 to get it down and smooth. I ended up with a triple blade 115mm tail system using 710mm Rotor Techs and it flew fantastic at 1000rpm with full tail authority until I lost it in a cloud filled background with the sun hitting it from behind. Oh well, time for the 800's. I am now flying it down to 850 and the fun has yet to start. I am setting it up as a scale trainer for very large helicopters so the goal is to add about 10 pounds to it and fly it no faster than 975rpm. I might try to bring it down to 800rpm to see how it handles so I am anxiously awaiting some parts to get in stock from MD. Have fun.

Don

[im4711]

Since I changed my fleet a little bit I also setup a new low rpm heli in my fleet.

My regular machines such as the Banshee 850 and 700 do run normally around 1200 - 1300 rpm on the lower end and go up to about 2000 rpm.
My Takumi is due to weight more a machine running between 1400 and 2000 rpm.

Two machines now are considered low rpm on my fleet. One is the old TDR1 with 753 mm main blades running at 800 rpm and 1000 rpm for slow motion 3d flying and one is my Diabolo L with 713 mm main blades currently running 900 - 950 rpm on the low end for slow motion 3d and 1800 o the high end.

If someone wants to fly around and hover mostly the rpm on 700 size helis should be possible to be down to about 650 - 700 rpm. In order to flip it around and (depending on weight of the heli) its most likely around 900 and up. For larger 750 - 800 size machines its even easy to do 3d flying at about 800 rpm.


Still getting some practice time on my Diabolo L to see if I can lower battery weight and therefore bring rpm down to 800. However I am happy with the current settings and results on the heli. Cool agility starts normally at about 1200 rpm.

[etherbatxx]

i run 1100rpm on my Gob 700 with 690mm main blades for sport and light 3d

i tried going lower but i don't have the skill set to pull it off.

[Luigi_tuga]

On the Logo 480, I'm running 1600 with RT blades. Haven't made a test to check the lowest HS to get it going.
1600 gives authority for agile flying, piro circuits, piro rainbows & flips, and gentle Tic toc.
Able to fly 8-9 minutes, love low HS.

[Luigi_tuga]

Today I lowered a bit more the HS, and had lots of fun at 1380, some nice low tone barks from the blades. May easily fly 12-13 minutes like this

[Wargamer]

I have been flying the Atom on 516s, and wondering how much lower to try for fun since it's still quite acrobatic at 1700. This suggests I have a good way to go, so thanks for sharing!

[Luigi_tuga]

Originally Posted by Wargamer

I have been flying the Atom on 516s, and wondering how much lower to try for fun since it's still quite acrobatic at 1700. This suggests I have a good way to go, so thanks for sharing!

You may lower that a few hundred, stretched atom is extremely lightweight.

Sent from my Nexus 7 using Tapatalk

[Luigi_tuga]

Well, upped the HS a notch to 1400, and pulling 12 minutes of gentle [very] 3d, 3.77 per cell.
Top of efficiency, as I'm flying cheap turnigy 3300 30 C 😂
Have fun with the long flights!

[Keyrigger]

Well, I was able to get the parts in time, for my flying vacation in Panama City and Virginia, and changed my MD-7 to an MD-8. With their three blade tail, 115's on the tail, and 810mm Rotor Tech Industrials, I managed to fly it down to 750rpm with good results. I did try it at 700 but a low speed wobble, related to the blade grip tension, prevented me from a nice, quiet flight. With a DFC head, I don't want to risk flexing the links, so I have increased it to 800rpm for good measure. I flew it this past week at the Spring Fling in Fredericksburg, VA. where everyone wanted to see this beast up close and find out how I did it and just how low the head speed was. I really like flying this monster now. Too much fun.

Don

[etherbatxx]

when the question is "how low can you go?",
does it mean fly around inverted, a loop, or "it barely got off the ground but i was able to fly out and back and land"?

[im4711]

Originally Posted by etherbatxx

when the question is "how low can you go?",
does it mean fly around inverted, a loop, or "it barely got off the ground but i was able to fly out and back and land"?

I guess that depends on each owner. If cruising around you can extend flight time a bit since you should have less current peaks and therefore less consumption.
For slow motion 3d on my Diabolo L with 12s 5000 mAh I pull up to 20 minutes of flight time with 900 rpm (that includes flips, rolls, pro flips ...).

[Luigi_tuga]

Originally Posted by etherbatxx

when the question is "how low can you go?",
does it mean fly around inverted, a loop, or "it barely got off the ground but i was able to fly out and back and land"?

I need full 3d capability on the lower HS, piro flips, piro funnels, flips and snakes.
For a nice loop, it needs to pick up some good speed.

[etherbatxx]

agreed.
i can go lower than i'm at, but just making slow upright passes up and down the field gets boring, fast.