Forward Engine blades ROTATING on DC-8, not on B707 !

[guy]

Hi all,

Why are the forward blades of the engines of the DC-8 ROTATING while those of the Boeing 707 do NOT ?

This seems to be true for the Turbojet version (Dc8-30, B707-320) and also for the Turbofan (DC8-50, B707-320B/C).

Thanks in advance and all the best.

Guy

[guy]

I have made some research on the net.
The Boeing 707 engines had so-called IGV's (Inlet Guide Vane) which were fixed and used to direct the airflow
on the fan behind and the DC-8 apparently didn't have those.
Also some military aircraft had VIGV's (Variable IGV)
The IGV's were not used on newer aircraft any more for , among others, noise reasons.

Guy

[Dee Waldron - HJG]

A lot of research goes into making our models. Trust us.
Guy's explanation is correct.

Dee

[guy]

I have made some more research.
ALL those old Jets had IGV's (Inlet Guide Vane):

The Boeing 707, 720, 727 and 737-100/200 .
The Sud Aviation Caravelle, the HS121 Trident, the BAC 1-11, the Vickers VC-10.
The Convair 880/990 had VIGV's ( variable pitch Igv)
The Douglas DC-9 all versions and the still flying MD80.

And also the Douglas DC-8 (except the 70's with the Cfm engines)
For the DC-8 you can see it very clearly on the video below(at 2:50) of the arrival of
a french Dc-8 with JT-3D engines at the Museum for Air and Space.

www.dailymotion.com/video/xrifbc_douglas-dc-8-sarigue-f-rafe-arrivee-en-vol-au-musee-de-l-air-et-de-l-espace-du-bourget_tech

I nevertheless like your DC-8's.
I had published some nice pictures of it on flightsim not long ago:

www.flightsim.com/vbfs/showthread.php?281008-Famous-dc-8

Guy