Chinook & other tandem rotors discussions
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Some Interior Pix
Some people posted some really impressive photos of CH47s from the outside, but I didn't see any interior ones, so I thought I'd put up a handful.
As a HHGTTG fan, I love:
Sorry for the poor quality, it was a quick grab of some photos...
These are exterior and not very exciting, but perhaps of some interest:
As a HHGTTG fan, I love:
Sorry for the poor quality, it was a quick grab of some photos...
These are exterior and not very exciting, but perhaps of some interest:
Wow! After all the development that went into making the 47D/E and they didn't even change the locking wire on the rotor heads!
Nice to see they haven't changed - I used to build 'em at ODI.
Nice to see they haven't changed - I used to build 'em at ODI.
Saturday Shows Crippling Flaws
The Chinook: big, slow, noisy and with a critical flaw. If you hit the interconnect shaft game over as the rotors collide and destroys the aircraft. On the V-22 take out the interconnect shaft and you get a caution light.
The Sultan
The Sultan
So......Sultan.....why have it at all then if it is excess to need? Would the Osprey not be much cheaper to build it did not have one? Is this a Bell way of upping the price much akin to the 500 Dollar Toilet seat or 700 Dollar Hammer we have heard so much of in the past?
I guess you shall try to convince us there is no way an RPG could hit an Osprey and not take out an engine and the shaft at the same time....eh?
Spent a lot of spare time thinking up these kinds of comments during your time off?
I cannot but wait to hear this explanation!
I guess you shall try to convince us there is no way an RPG could hit an Osprey and not take out an engine and the shaft at the same time....eh?
Spent a lot of spare time thinking up these kinds of comments during your time off?
I cannot but wait to hear this explanation!
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You know, I remember the scandal about those 500 dollar toilet seats and 700 dollar hammers when I was in school and was outraged. Now that I have had plenty of years in aviation and am aware of the cost of aviation related tools and components I realize all of the complaints about those prices were from media idiots and political grandstanding. You can barely buy a nut or bolt from Sikorsky or Bell for those prices and that is on the commercial side, nit the military.
Huey,
Along about that time I was involved in Fraud Investigations for what is now NCIS. In a training class at the Navy Supply School in Athens, Georgia....an Officer there tried to explain away how all that so innocently happened and how there really wasn't a problem and there was no attempt to cheat the Navy.
His example was the accounting method used to figure the costs of each line item within the contract. At the time he was speaking I happened to have a General Services Catalogue on the desk next to my notebook. As he talked, and I was taking notes of what he was "teaching" us.....I keyed on something he said having made the note.
He was talking about hand tools....and how the accounting method was really the problem. He flashed on the viewing screen part of the contract that applied to what he was saying. In that list was a thing called "Device, Impact, Manually operated". A layman would have called it a "Hammer" and a Specialist would have called it a" 12 ounce Ball Peen Hammer".
I went to the GSA Catalogue and roamed through the Hammer section and found literally hundreds of different kinds of hammers, wedges, mallets, ball peen hammers, tack hammers, roofing hammers, claw hammers, sheet rock hammers, brick hammers....you get my point.
He was dumbstruck when I told him of that and the fact at no point was there an entry for "Device, Impact, Manually operated" anywhere in the GSA catalogue.
He got really flumoxxed when I asked him why the builder of the F-18 did not just call it a fecking hammer instead of what they did if they were not trying to pull a fast one?
A hammer is a hammer is a hammer.....is it not?
One outcome of those investigations was a program called BOSS....Buy Our Spares Smart....that encouraged employees to challenge any questionable pricing and rewarded them with percentages of the savings made. A simple practice borrowed from the private sector historically unknown to government.
Along about that time I was involved in Fraud Investigations for what is now NCIS. In a training class at the Navy Supply School in Athens, Georgia....an Officer there tried to explain away how all that so innocently happened and how there really wasn't a problem and there was no attempt to cheat the Navy.
His example was the accounting method used to figure the costs of each line item within the contract. At the time he was speaking I happened to have a General Services Catalogue on the desk next to my notebook. As he talked, and I was taking notes of what he was "teaching" us.....I keyed on something he said having made the note.
He was talking about hand tools....and how the accounting method was really the problem. He flashed on the viewing screen part of the contract that applied to what he was saying. In that list was a thing called "Device, Impact, Manually operated". A layman would have called it a "Hammer" and a Specialist would have called it a" 12 ounce Ball Peen Hammer".
I went to the GSA Catalogue and roamed through the Hammer section and found literally hundreds of different kinds of hammers, wedges, mallets, ball peen hammers, tack hammers, roofing hammers, claw hammers, sheet rock hammers, brick hammers....you get my point.
He was dumbstruck when I told him of that and the fact at no point was there an entry for "Device, Impact, Manually operated" anywhere in the GSA catalogue.
He got really flumoxxed when I asked him why the builder of the F-18 did not just call it a fecking hammer instead of what they did if they were not trying to pull a fast one?
A hammer is a hammer is a hammer.....is it not?
One outcome of those investigations was a program called BOSS....Buy Our Spares Smart....that encouraged employees to challenge any questionable pricing and rewarded them with percentages of the savings made. A simple practice borrowed from the private sector historically unknown to government.
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I think, that I have discovered the reason why my tandem loops on take off! I just want to see what the experts here on the forum think... The flapping hinges are too weak that allows the advancing blade angle to pitch up and with precession the result is a pitching up moment at the front of the rotor disk. What do ya think?
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I think, that I have discovered the reason why my tandem loops on take off! I just want to see what the experts here on the forum think... The flapping hinges are too weak that allows the advancing blade angle to pitch up and with precession the result is a pitching up moment at the front of the rotor disk. What do ya think?
As for Sultan's comments about the CH-47 being big, slow, noisy, etc., I would not necessarily call the CH-47 slow. I believe it's as fast as the current CH-53, and a bit faster than the current UH-60. The fore/aft driveshaft on the CH-47 is indeed much more critical than the interconnect shaft of the V-22. The forward rotor of the CH-47 is driven by this driveshaft alone, so a failure here would mean a loss of the aircraft.
A civilian Chinook was lost near the Shetlands because of this - wasn't the shaft, but the forward gearbox corroded and failed (from memory, correct me if I'm wrong, someone). See AAIB report here.
And as for speed, RAF Chinooks in Afghanistan have been known to outrun their Apache escorts if they need to get back to the medical facilities at Bastion in a hurry.
And as for speed, RAF Chinooks in Afghanistan have been known to outrun their Apache escorts if they need to get back to the medical facilities at Bastion in a hurry.
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Hook are slow!!!
When I was in Vietnam, we routinely had to asked the Chinooks to slow down! 
rif raf,
I was using different hinge materials at that time. I was never sure if it was the design or poor material choices. I later disovered what the problem was...it was my choice of airfoils. I was using an 8H12 airfoil blades that has an up reflex to it. When the blade start to advance, the up relex made the blade pitch up uncontrollable. Over time, I had changed the head design several times but still had the pitch up problem. The only common factor was the 8H12 airfoil. Then I changed the blade airfoil to a profile with a slight down relex...it now works better. The model still pitches up but not to where it's uncontrollable.
Now I'm working on the control mixing. At this scale, any change is difficult. To begin the work on the controls I'm using the MC-4 tandem helicopter's lay-out as a refence. It's the simplest control system that I can find.
rif raf,
I was using different hinge materials at that time. I was never sure if it was the design or poor material choices. I later disovered what the problem was...it was my choice of airfoils. I was using an 8H12 airfoil blades that has an up reflex to it. When the blade start to advance, the up relex made the blade pitch up uncontrollable. Over time, I had changed the head design several times but still had the pitch up problem. The only common factor was the 8H12 airfoil. Then I changed the blade airfoil to a profile with a slight down relex...it now works better. The model still pitches up but not to where it's uncontrollable.
Now I'm working on the control mixing. At this scale, any change is difficult. To begin the work on the controls I'm using the MC-4 tandem helicopter's lay-out as a refence. It's the simplest control system that I can find.
Last edited by joe nelson; 7th Jan 2012 at 15:15.
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Gearbox failure
Nr,
Does the Chinook have a chip detector in the front gearbox? I would have thought that for something as serious as a gearbox failure there would be some indication like a chip light.
Does the Chinook have a chip detector in the front gearbox? I would have thought that for something as serious as a gearbox failure there would be some indication like a chip light.
ISTR 5 Mag-Chips - Each Engine Nose Box, Aft & Fwd Boxes and finally the Combiner - all with Fuzz-Burners (well they did in my time!)
Any "Light" deserved a short notice landing - Nowadays I suppose there must be an ultra-serious think about carrying on for more than the current height!
Any "Light" deserved a short notice landing - Nowadays I suppose there must be an ultra-serious think about carrying on for more than the current height!
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I'll have to see if I can dig up some of the cooler pics I have laying around. Of the more unusual are a few of me slinging another Chinook which got shot down while we were in Afghanistan. The bird I was flying was your typical OD green while the dead bird was the new desert tan junk. I'll leave it up to you to determine if this paint scheme is worthy.
Actually....neither paint scheme is worth a damn.
As we do not have to worry about Oppo Air.....thus no need to blend in with the terrain beneath us....why not paint them to blend in with the sky above us as that is the direction the bad guys are looking (generally). If they are looking down at the aircraft....it is from a hill/ridge/mountain and thus close enough to make out the aircraft no matter what color or pattern they are.
As we do not have to worry about Oppo Air.....thus no need to blend in with the terrain beneath us....why not paint them to blend in with the sky above us as that is the direction the bad guys are looking (generally). If they are looking down at the aircraft....it is from a hill/ridge/mountain and thus close enough to make out the aircraft no matter what color or pattern they are.
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Since I started this thread , it seems Ive grown very old, and yet only just seen the pictures of the business end of a 47, looking at the cockpit end it looks and seems just like that of any other large Heli, so how quickly can an existing Heli pilot get to grips with the physical side and fly one away, a Ch47 that is.
Thank you for all the input I have just re-read many of the entrys, and I am still MAD KEEN to get in one and see what happens, I am also green with envy when my boy tells me how good they are in the Afghan area.
Peter R-B
formerly VfrpilotPB
Thank you for all the input I have just re-read many of the entrys, and I am still MAD KEEN to get in one and see what happens, I am also green with envy when my boy tells me how good they are in the Afghan area.
Peter R-B
formerly VfrpilotPB
The trick to flying the Chinook is learning how small it is.
In time...some folks can get the "feel" for where the Cargo Hook is and how high off the ground the aft gear are....but it is a rare pilot that can also "feel" where the Aft Gear is.
When it came to putting the Aft Gear down on a Rice Paddy Dike....that took some doing. Putting the Cargo Hook into the Hook Up guy's hands was no mean trick but even some never got it figured out.
Pitch Attitude and knowing which particular Pitch attitude was needed or what Cyclic Stick Position was needed when doing maneuvers with the aft gear or sometimes forward gear in contact with the ground took some getting used to as once the gear were on the ground....two inches of aft cyclic glued the gear and then all pitch attitude control was done by use of the Thrust Lever (Collective Lever).
In time...some folks can get the "feel" for where the Cargo Hook is and how high off the ground the aft gear are....but it is a rare pilot that can also "feel" where the Aft Gear is.
When it came to putting the Aft Gear down on a Rice Paddy Dike....that took some doing. Putting the Cargo Hook into the Hook Up guy's hands was no mean trick but even some never got it figured out.
Pitch Attitude and knowing which particular Pitch attitude was needed or what Cyclic Stick Position was needed when doing maneuvers with the aft gear or sometimes forward gear in contact with the ground took some getting used to as once the gear were on the ground....two inches of aft cyclic glued the gear and then all pitch attitude control was done by use of the Thrust Lever (Collective Lever).