That was you flying one of those d**n things over my house at 7pm every day? At 500’msl? Slowly? For the past 20 yrs? 😂
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Just to piggyback off the experts
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Yea the scorpion motors (and tengu for that matter) in this size are 10 pole. The HSM-800 mechanics are the same across the board for 700/800 in gear ratio which is 13.8. I would definitely just get that sorted just to make sure you know what speed your tail is going... 1150-1200 (without the low rpm upgrade) could be a just bit to slow for the tail to maintain TA with the fuselage blocking some of the air. If you have some 115mm tail blades to try at that headspeed.Comment
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I did a lot of flying in the Ft. Hood area and west of there out around San Angelo, so it’s possible depending on where you live in Texas:)Comment
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Thanks, I got the head speed issues sorted thanks to the good folks on this thread. I also ordered some 115mm tail blades and will give them a try when they arrive. What is the minimum head speed recommended without the low rpm upgrade?Originally posted by sfcfury View PostJust to piggyback off the experts!!
Yea the scorpion motors (and tengu for that matter) in this size are 10 pole. The HSM-800 mechanics are the same across the board for 700/800 in gear ratio which is 13.8. I would definitely just get that sorted just to make sure you know what speed your tail is going... 1150-1200 (without the low rpm upgrade) could be a just bit to slow for the tail to maintain TA with the fuselage blocking some of the air. If you have some 115mm tail blades to try at that headspeed.Comment
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So I ordered a tach as sfcfury suggested to get an idea on my head speeds I run, this way maybe I can be of better help in that dept., I'm still learning these big scale heli set ups myself, but my question is, why run such low head speeds and not have good tail authority when you can just bump it up a little and have good tail control?? I told you guys I'm no expert on this, not joking....
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I would just start at 1400rpm and work my way down... I mean ultimately as long as you don't exceed the VNE speed of the rotor system you will be ok lol...Originally posted by tip22v View PostComment
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Oh boy, I know I'm in trouble if we have VNE restrictions on these scale birds, I have exceeded them plenty of times...Originally posted by sfcfury View Post
Shoot, found out my tach won't be here until maybe February, didn't look at where it was coming from, oh well not much flying anyway with all the rain we have been getting here in Ca., but I did get two flights in on the Apache yesterday in between storms.Comment
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My house is just across Tabbs Bay from Ellington Field in S. Houston. These are Texas ANG boys that fly their training routes so guess you ain’t the culprit,😂Comment
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Just spitballing here (because sfcfury has run me out of money and I can no longer shop online) but I try to set whatever HS is required to give me a hover pitch of around 6-6.5 degrees. My goal was to keep the stick uniform for all my helis regardless of weight. Some guys like 5 degrees but that’s a little higher HS than necessary for heavy scale flying, IMO.Comment
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If my memory serves me the headspeed on the full scale Apache is 235 rpm, with the blade tips spinning at ~435kts. Vne for the blades themselves is all about air temperature because, for example, at 20 deg F the blade tips enter the transonic range with a forward airspeed of only 150 kts, I can tell you from personal experience the Apache is capable of straight and level speeds well in excess of 150 kts, especially with low air temp, low density altitude and no armament. When the blade tips reach the transonic region the center of pressure begins to move aft (starting at the tip of the blade), which causes the blade to twist and could cause the blade to delaminate at the blade root (don't ask me how I know this...) Fortunately, these RC helis have much smaller rotor diameters so even though we are flying head speeds that are 5 times or more what a full scale would fly there is little danger of the blades going supersonic:)Originally posted by sfcfury View PostComment
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Whew, yep that was not me...but I can guarantee you I've riled some folks over in west Texas:).Originally posted by PawPaw View PostComment
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Success! I set the Pulse per Revolution per your formula and that fixed my problem:). It's really cold here in the Pacific Northwest today (25 deg F) so I only hovered in my driveway for about a minute or so, but she lifted up straight, was pretty stable in pitch and roll, and the tail felt was very locked-in. My head speed was 1250. I know the folks from Minnesota are laughing at me for saying 25 deg is cold, but that's cold for here:). It hovered just a tad over half stick, about 6 deg. Now that I know she is behaving I need to take it out to our field for some more extensive hover testing, blade tracking adjustments, etc.Originally posted by PawPaw View Post
Thanks everyone for the help, I was almost ready to give up on this one, you saved the day! -TomComment
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Sounds like you were trying to keep up with some Chinook's (j/k)... or just doing what joe's do... test the limits of the equipmentOriginally posted by tip22v View Post
I was being a little silly about the 'VNE' speed, but I will say that my Vario 815mm blades that I got for my UH-1 had a big fat do not exceed 1270 rpm on the package. I'm sure that there has to be some buffer to that, and it seems like all the Roban blades in that size will go to at least 1400...
I know in the scale community there's a push to get the lowest stable head speed possible, for the 'scaleness' and no doubt that helps with battery efficiency and wear and tear on the components etc., but I'm kind of along the thoughts of DC, if I can run 100 rpm faster and have more power/lift to play with... why not?Comment
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At 25F my nipples could cut glass.😁Comment
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Chinooks are very fast, we could never keep up with them:).Originally posted by sfcfury View Post
Sounds like you were trying to keep up with some Chinook's (j/k)... or just doing what joe's do... test the limits of the equipment
I was being a little silly about the 'VNE' speed, but I will say that my Vario 815mm blades that I got for my UH-1 had a big fat do not exceed 1270 rpm on the package. I'm sure that there has to be some buffer to that, and it seems like all the Roban blades in that size will go to at least 1400...
I know in the scale community there's a push to get the lowest stable head speed possible, for the 'scaleness' and no doubt that helps with battery efficiency and wear and tear on the components etc., but I'm kind of along the thoughts of DC, if I can run 100 rpm faster and have more power/lift to play with... why not?
I agree, having a little extra power is nice...Comment
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That one made me laugh out loud, my wife looked at me kind of funny.....Originally posted by PawPaw View Post
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With no idea on my head speeds, I am a little worried about parts failure eventually, I am watching the gears and certain parts closely and keeping everything lubed very well, can't wait to get my new tach to see where I'm at on the Apache, now my Magnum PI Hughes500, OH-6, AH-6 and Cobra seem okay to me, Apache is the only one I think I'm high on head speed because its so heavy and with only 700mm blades, I might try the 750mm blades off the OH-6 again, along with the 115mm tail blades, see if I can slow it down a bit on mine.
tip22v that is great news you got it to hover well, its the overall performance in forward flight and transitioning from forward flight to hover that you might find slow and sluggish, it will drop on you quick if the head speed is to slow, the Apache is like flying a jet, you have to stay ahead of it at all times...
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My head speed on my Apache sounds about like this one in the video, its actually the video I kind of went by when I realized mine was not going to fly good at a low scale head speed, you guys think that's this is one is around 1400 rpm or so??
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