Mi-8 service ceiling ?

Since we have no manual to refer to, I am trying to get info from the net in order to get a proper training course in place within our squadron for this chopper.

Working on the mountain flight training module, I found several sources explaining the max service ceiling for the Mi-8 is between 4200 to 4800 (wiki). Army technology website is gving 6000m.

I flew last night and was able to fly above 6400m and land quite easily on top of a 5400m high mountain. This by the way totally outperform the Ka50 in DCS with his 5500m. But at least, ka50 service ceiling in DCS is consistent with information found on the net.

So what is the truth? Is DCS Mi-8 model really matches real life altitude performances or is it flawed?

M,,-17-1B.Flight manual
2. LIMITATIONS
2.1. Weight limitations
(1) Normal takeoff weight... 11100 kg
(2) Maximum takeoff weight... 13000 kg
(3) Maximum useful load 4000 kg
(4) Maximum external load weight... 3000 kg
Note: The maximum takeoff weight for flying over mountains areas at high
ambient temperatures is determined for the actual ambient conditions
at the take-off field from the graphs included in subsection 1.6, but in
all cases the maximum takeoff weight shall not exceed 13000 kg.
2.2. CG Limitations
(1)Forward CG limit is +300 mm (forward of main rotor rotation axis)
(2) Aft CG limit is -95 mm (aft of main rotor rotation axis)
2.3.Weather limitations
(1) Operation of the helicopter is allowed at ambient temperature within the
range of -50 to +50 "C.
(2) Flying in clouds is allowed at altitude up to 3500 m.
2.4. Performance limitations
(1) It is allowed to climb, to perform horizontal flight, power-on and autorotation
glide within the speed range indicated in Table 2.1.
Table 21
lAS limits, km/h
Altitude, m 13000 kg takeoff weioht 11100 ko takeoff weioht
maximum minimum maximum minimum
Uo to 1000 230 60 250 60
2000 195 60 230 60
3000 160 60 210 60
4000 120 60 170 60
4800 100 60 - 60
5000 - - 130 60
6000 - - 100 80
Notes: 1. At the normal takeoff weight and CG at the aft limit (with the
common center of gravity of cargo aligned with the respective red
arrow at the RH side wall of the cargo compartment) the maximum
flight speed is limited by 240 km/h.
2. At a gross weight exceeding the normal gross weight and with
the negative center of gravity the maximum flight speed in climb is
limited by 220 km/h.
(2) To improve safety of flight it is allowed to perform hovering at altitudes indicated
in Table 2.2. At altitudes exceeding those indicated in Table 2.2
hovering is allowed during transportation of external load and due to tactical
considerations.
2-3
Mll-17-1B. Flight manual
Table 2.2
Takeoff wei ht, k Hoverin altitude,m
11100and below U to 10
Above 11100 I Upto 5
Do not hover within the range of altitudes differing from those indicated in
Table 2.2 down to 110m, except for the cases of extreme urgency.
(3) The maximum speed in horizontal flight with the cargo doors semi-open
(for transportation of the main rotor blades and other bulky cargo items) is
230 km/h, and 200 km/h with the doors removed.
(4) Flying over heavily broken terrain is allowed at an altitude of not less than
20 rn and lAS not less than 60 km/h.
(5) The minimum allowed altitude is 15 m over even terrain and 150 m for flying
by night.
(6) Turn in hovering at angular rates not exceeding 12 deg/s.
(7) The time of full reversal of the pedals necessary to change the helicopter
sense of rotation should be not less than 3 s.
(8) It is allowed to execute 360-degree turns in hovering near the ground at a
wind speed not exceeding 10 rn/s,
(9) It is allowed to start and stop the main rotor and to execute hovering,
takeoff and landing at wind speeds indicated in Table 2.3.
Table 2 3
(10) TaxIIng IS allowed at a Wind speed not exceeding 15 mIs, at
headwind nor exceeding 25 rn/s,
(11) Power-on glide is allowed within the range of speeds indicated in
Table 2.1.
(12) Autorotation glide is allowed within the range of speeds indicated in Table 2.1.
(13) Turns with the main rotor autorotating are allowed with bank angles not
exceeding 20°.
(14) The maximum main rotor speed (read on the tachometer indicator)
is allowed for not more than 20 s:
- 101% at engine power above cruising 2.
- 103 % at engine power below cruising 2.
(15) The minimum allowed main rotor speed (speed drop):
In flight in transient conditions is 88 % (on the indicator) for a period not
exceeding 30 s.
The minimum allowed main rotor speed during autorotation landing is 70 %.
To avoid a main rotor speed drop during execution of various maneuvers
involving acceleration of the engines move the collective pitch control
lever from idle to maximum power within a period of time not less than 5s.
To prevent the main rotor overspeed above the allowed maximum limit
the colleCtive pitch control lever downwards motion rate should not exceed
1 deg/s (except for the cases of engine failure).
(16) It is allowed to engage the An"346 autopilot altitude channel in horizontal
flight at an altitude not less than 50 m.
(17) It is allowed to execute turns and spirals within the allowed range of airspeeds
at bank angles indicated in Table 2.4.
Maximum allowedwind speed, m/s
Wind direction At mainrotor startingand At takeoff and landing
stooolno
Headwind 25 25
Rightside crosswind 10 10
Left side crosswind 15 10
Tailwind .. 8 10
2-4

This is for the Mi-17 the formatting did not copy well but it goes up to 6000m in the table. You can find this in Mi-8MTV2 docs:thumbup:

Ok. Thanks Cibit.

There are different modifications of the Mi-8 with very different characteristics- keep that in mind. A Mi-8MTV with ukrainian ТВЗ-117ВМА-СБМ1В engines manufactured by Motor-Sich reached 8100 meters in 2010. In 2013 the Mi-8MSB with the same engines reached 9150 meters which is higher than Everest.

@Gloom Demon: Those helicopters are unique and not in series production, yet.

The flight manual states:

- with normal take off weight 11100 kg: 5000 meters

- with max take off weight 13000 kg: 4100 meters.

When engine and blade anti-ice system turned on, subtract 200-300 meters. And for helicopters equipped with EVU (exhaust gas cooling device) subtract another 150-200 meters.

Well, I was max fuel, no external loads and happily climbing above 6000++

@Gloom Demon: Those helicopters are unique and not in series production, yet.

The first serial Mi-8MSB has been rolled out in September, 2013 by the Orsha Aviaremontniy zavod - I believe it's that aircraft repair plant Motor Sich bought in Byelorus a couple of years ago. One must underdstand, though, that record-breaking aircraft are usually tuned up a bit. I would presume, that at 9 km. one would need an oxygen mask, at the very least.

So what flight manual are you guys (Cibit and Press) referring to? Why is it different?

The Mi-8MSB is practicly a vanila Mi-8 with steroids. Instead of the TV2 engines, Motor Sich installed TV3.

Anywho, how many helicopters are equipped with the TV3-117VMA-CBM1V engines?

I believe the question was addressed for the helicopters with TV3-117MT/VM engines. Also if the manual states the the max altitude is 5000 meters it doesn't mean it won't go further up.

@BaD CrC: I have my own flight manual copy as I am an engineer. It's not in English though. We have here Mi-17 with TV3-117VM engines.

I was quoting from the Mi-17 english flight manual that is located in the Mi-8 docs folder;)

Mi-8 equipped with TV3-117VM engines...

Normal takeoff weight: 11100 kg

Maximum takeoff weight: 13000 kg

Service ceiling:

At normal takeoff weight: 6000 m

At maximum takeoff weight: 4800 m

Just having fuel full is not going to get you to 11000 kg, you're probably only around 9500 kg...I think it tells you your weight in the mission planner where you add weapons and fuel, etc.

In other words, you should be able to get well beyond 6000 meters with just fuel fuel and nothing else.

Since we have no manual to refer to, I am trying to get info from the net in order to get a proper training course in place within our squadron for this chopper.

Working on the mountain flight training module, I found several sources explaining the max service ceiling for the Mi-8 is between 4200 to 4800 (wiki). Army technology website is gving 6000m.

I flew last night and was able to fly above 6400m and land quite easily on top of a 5400m high mountain. This by the way totally outperform the Ka50 in DCS with his 5500m. But at least, ka50 service ceiling in DCS is consistent with information found on the net.

 

So what is the truth? Is DCS Mi-8 model really matches real life altitude performances or is it flawed?

Just to say the Ka-50 will get to 6000m without weapons and with plenty of fuel, (take off at about full fuel and I managed it fine)

A note about the Wikipedia entries for the Mi-8/17...

The "Mi-8" entry (http://en.wikipedia.org/wiki/Mi-8) is for the "older" versions (Mi-8T,P,S,etc.), equipped with TV2-117 engines.

The "Mi-17" entry (http://en.wikipedia.org/wiki/Mi-17) is for the "newer" versions (All Mi-17, Mi-8M,MT,MTV,etc.), equipped with TV3-117 engines.

Other than the one Motor Sich showed at the Aviasvit 2010, I would guess two... or three :D But that does not make the Mi-8MSB not a serial chopper.

I'm not a big helicopter guru, but I would presume that the flight manual recommendations are based on safety concerns and most real world hardware can easily outperform them.

I think it depends on the request of the customer. If the customer operates in high altitude conditions revisions are made to the helo and manuals so it will allow operating in high conditions.

We here have 3 Mi-17s, 1 VIP and 2 standard. Although the engines are the same, the VIP helicopter cruise speed is at 270km/h. It naturally stays at 270km/h with no vibrations. The other two their cruise speed is at 230km/h.

So, go figure :joystick:

And the nonVip ones vibrate at 270?

At 255-260 they start to vibrate.

скажу вам по секрету - сейчас в мире ДКС из всех вертолетов, Ка-50 летает выше всех.)))))))

Ка-50 - 8700м

Ух-1 - 8300м

Ми-8 - 7700м

What a high quality information guys. Thanks.

Alphaonesix: I'll check indeed my mi8 weight again.

Namenlos Ein, great idea for a misision in DCS.

Shadowowweosa: my russian is a bit poor. You mean the secret in DCS is that ka50 can fly at 8700m?

Shadowowweosa: my russian is a bit poor. You mean the secret in DCS is that ka50 can fly at 8700m?

да, именно так.

ка-50 - 8700м

At 255-260 they start to vibrate.

Is you VIP bird equipped with a rotor vibration damper and the others are not?

Is you VIP bird equipped with a rotor vibration damper and the others are not?

All of them have vibration dampers, no PZUs, VM engines.

Well keep in mind that service ceiling really means that the answer to the question, "Can the aircraft safely and reliably perform it's normal workload at this altitude even if multiple things start going wrong in quick succession," is a qualified yes issued by engineers and test pilots.

Engineers and test pilots are fairly conservative in issuing recommendations because they have to keep in mind that some of the people who read their recommendations may be incompetent fools who also happen to have no sense of self preservation.

So in good conditions it's not surprising if an aircraft can exceed it's official specs by a large margin.

The advisable flight envelope is what gets printed in manuals, the possible flight envelope is almost always much bigger, but a lot of the extra is in the category filed under 'really stupid ways to die.'

The inability to keep flying after 40 or more fatal crashes in real life may also have something to do with where real manuals draw the line between can do and should do. As does the cost of returning a heap of flaming wreckage to an airworthy state.

Why mi-8/17/171 is having dangerous wing 4-6 m/s tail wind?? Any one plz clarify. Why not more